*NCCT is approved as a provider of continuing education programs in the clinical laboratory sciences by the ASCLS P.A.C.E. Program, provider #122.

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1 COURSE DESCRIPTION Blood cultures are vital for the identification of microorganisms that cause sepsis. However, if not collected properly, false positive test results can occur, leading to unnecessary treatment and increased length of hospital stay. This CE course will discuss sepsis and related disorders, preanalytical variables of importance to the collection of blood cultures, and procedures for collecting blood cultures. *Valid for P.A.C.E. credit through 12/31/2019* * ASCLS P.A.C.E. is an approved continuing education agency by the California Department of Health Laboratory Field Services, Accrediting Agency #0001. *NCCT is approved as a provider of continuing education programs in the clinical laboratory sciences by the ASCLS P.A.C.E. Program, provider #122. Rev 3 March 2016 COPYRIGHT 2013 National Center for Competency Testing Reproduction or translation of any part of this work beyond that permitted by Sections 107 or 108 of the 1976 United States Copyright Act without the permission of the copyright owner is unlawful. No part of this work may be reproduced or used in any form or by any means-graphic, electronic, or mechanical, including photocopying, recording, taping, or information storage and retrieval systems without written permission of the publisher. 1

2 COURSE TITLE: Sepsis and Blood Culture Specimen Collection Author: Lucia Johnson, MA Ed, MT(ASCP)SBB Vice President, Recertification National Center for Competency Testing Number of Clock Hours Credit: 1.0 Course # Level of Instruction: Intermediate P.A.C.E. Approved: _X Yes _ No OBJECTIVES Upon completion of this continuing education course, the professional should be able to: 1. Define bacteremia, SIRS, sepsis, severe sepsis, and septic shock. 2. Identify the purpose of blood culture collection. 3. Describe five preanalytical errors. 4. Describe specimen collection, including site preparation and use of safe needle devices. 5. List equipment needed for blood culture collection. 6. Describe methods used to collect blood for blood cultures. 7. Identify the importance of minimizing preanalytical errors. Disclaimer The writers for NCCT continuing education courses attempt to provide factual information based on literature review and current professional practice. However, NCCT does not guarantee that the information contained in the continuing education courses is free from all errors and omissions. 2

3 INTRODUCTION A blood culture is a laboratory test where a whole blood sample is placed in liquid culture media to determine if microorganisms, specifically bacteria or fungi, are present in the blood system of the patient. If bacteria or fungi grow in the culture media, more tests are performed to identify the type of bacteria/fungi present and specific type of antibiotics to use to eradicate the microorganism. Blood cultures will not detect infections caused by viruses or parasites. The presence of bacteria in the blood is called bacteremia. The presence of fungi in the blood is called fungemia. For the purposes of this CE course, the term bacteremia is used for both the presence of bacteria or fungi in the blood. Both aerobic and anaerobic bacteria can cause bacteremia. Aerobic bacteria are those that require oxygen for survival and growth. Examples of aerobic bacteria include Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli, and Neisseria meningitidis. Anaerobic bacteria are those that can survive and grow in the presence of little or no oxygen. Examples of anaerobic bacteria include Clostridium perfringens, Bacterioides fragilis, Actinomyces israelii, and Propionibacterium acnes. Examples of fungi that can cause bacteremia include Candida spp. and Histoplasma capsulatum. Bacteremia can lead to the development of Systemic Inflammatory Response Syndrome (SIRS) which in turn can cascade into sepsis, severe sepsis, and septic shock. Without appropriate and aggressive treatment, these disorders result in significant morbidity and mortality. Studies have shown the following in hospital death rates. Suspected infection 2% Sepsis 1.3% Severe sepsis 9.2% Septic shock 28.0% SIRS AND SEPSIS The presence of bacteria/fungi in the blood can lead to the development of Systemic Inflammatory Response Syndrome or SIRS. SYSTEMIC INFLAMMATORY RESPONSE SYNDROME (SIRS) This term was created in 1992 by a panel of members of the American College of Chest Physicians and Society of Critical Care Medicine. It is used to describe the body s response to inflammation. The inflammatory response occurs when tissues and cells are damaged. It is important to note that SIRS is nonspecific and can be caused by conditions other than bacterial/fungal infections such as toxins, trauma, and severe 3

4 burns. The inflammatory response is a self-defense mechanism the body initiates to save itself from the offending condition, such as a bacterial infection. When cells are damaged they release powerful chemicals including histamine, prostaglandins, and bradykinin. These chemicals cause fluids to leak into the tissues, causing swelling. This is a protective mechanism to isolate the offending substances, such as bacteria, from further contact with body tissues. The chemicals also attract other cells to help destroy the offending substance. At least two of the following criteria must be present to diagnose SIRS. Heart rate > 90 beats per minute Temperature > F or < 96.8 F Respiratory rate >20 breaths per minute or PaCO 2 < 32; PaCO 2 is the partial pressure of carbon dioxide in the blood one of the blood gas measurements White blood cell count >12,000/µL or < 4,000/uL or >10% band neutrophils (a white blood cell that fights infection) Treatment of SIRS is based on elimination of the underlying cause of the inflammatory response. If the cause is bacteremia, antibiotic therapy is started. SEPSIS The diagnosis of sepsis is made when the patient has SIRS and a bacteria or fungus is grown and identified in a blood culture. The site of the infection with microorganisms can also be identified in urine culture, sputum culture, wound culture, etc. The term septicemia is sometimes used instead of sepsis. However, sepsis is the preferred medical term for the body s systemic reaction to infection. The earliest signs/symptoms of sepsis include rapid breathing and altered mental status, along with the signs/symptoms of SIRS listed above. Other signs/symptoms include the following. Overall weakness Confusion Severe headache Shortness of breath Pain in abdomen Skin redness Draining wounds Aggressive antibiotic therapy must be given when a patient is diagnosed with sepsis. If not adequately treated, sepsis can lead to severe sepsis and septic shock, both of which have high mortality rates. SEPSIS The diagnosis of sepsis is made when the patient has SIRS and a bacteria or fungus is grown and identified in a blood culture. 4

5 General Information about Sepsis Annually, about 1 million people in the United States develop sepsis; at least 200,000 of them die. The incidence of sepsis is rising as the population ages. Sepsis can develop from any type of infection in the body. The most common infections that lead to the development of sepsis follow below. Included is the percentage of sepsis cases arising from the infection source. Bronchopulmonary infections 40%; community-acquired pneumonia is the most common cause of sepsis Abdominal infections 30% Urinary tract infections 10% Other infections 20% Risk Factors for Sepsis While sepsis can occur in anyone, the following individuals are at greater risk. Newborns Elderly Patients with severe trauma such as burns, motor vehicle accidents, gunshot wounds, etc. Patients with weakened immune systems, i.e., HIV/AIDS, chemotherapy, bone marrow/stem cell/organ transplants, etc. Hospitalized patients, especially those with urinary catheters, intravenous lines, indwelling venous/arterial lines, breathing tubes Patients with chronic diseases such as diabetes Patients who have had surgery, especially complicated surgery Patients with the following are also at increased risk for the development of sepsis. IVs for > 1 week Central IV lines Intra-abdominal or pelvic infections Splenectomy Meningitis Diverticulitis, Crohn s disease, cholecystitis Pyelonephritis, kidney stones, prostate enlargement Diabetes, alcoholism, chronic conditions 65 years of age or older Treatment of Sepsis Sepsis treatment consists of the following. Aggressive antibiotic therapy to kill the cause of the infection. 5

6 Maintenance of blood pressure to ensure the patient s organs and tissues receive adequate blood flow. This includes IV fluids to maintain the blood pressure and medications to increase the blood pressure. SEVERE SEPSIS Severe sepsis is diagnosed when a patient has sepsis and has signs of organ damage or decreased blood flow to tissues. Signs of severe sepsis include decreased urine output, increased bilirubin, low platelet count, lack of bowel sounds, increased lactic acid, low blood pressure, and change in mental status. Treatment of severe sepsis includes continuing antibiotic therapy and aggressive treatment with crystalloids IV solutions to increase blood flow to tissues and organs. SEPTIC SHOCK Septic shock is diagnosed with a patient meets the criteria for severe sepsis, and has a systolic blood pressure < 90 mmhg or a mean arterial pressure < 60 mmhg or a decrease in systolic blood pressure > 40 mmhg. Even with aggressive fluids being given via IV, patients remain hypotensive and exhibit organ dysfunction and/or failure. Additional treatments include ventilation to support pulmonary function, dialysis to support kidney function, and insertion of a feeding tube. BLOOD CULTURE SPECIMEN COLLECTION When sepsis is suspected, the physician orders blood cultures. Specimen collection for blood cultures is more detailed than that for routine venipuncture. There are several preanalytical variables that can result in unreliable test results, which in turn can lead to incorrect diagnosis and treatment of the patient. PREANALYTICAL VARIABLES There are five primary preanalytical variables that can affect the reliability of blood culture test results. These include timing of collection, number of blood cultures collected, volume of blood added to bottles, distribution of blood between aerobic and anaerobic bottles, and disinfection of the skin. Blood cultures are collected in sets that include one bottle for the study of aerobic bacteria and one bottle for the study of anaerobic bacteria. Preanalytical Variable 1: Timing of collection While very few studies have been performed, data does indicate that an influx of bacteria into the bloodstream occurs about one hour before the patient develops a fever and chills. Therefore, blood cultures are generally collected when the patient has a temperature spike, and then following at arbitrary intervals of minutes, or three blood culture bottle sets per episode of fever and chills. 6

7 Preanalytical Variable 2: Number of blood cultures Well documented studies have shown that the collection of at least three sets of blood cultures provides the best chance of identifying pathogenic bacteria/fungi in the blood. In fact, the collection of single blood cultures is not recommended at all except in two situations: suspected bacterial endocarditis and pediatric patients. Preanalytical Variable 3: Volume of blood Probably the most important variable in detecting the presence of pathogenic bacteria in blood is the amount of blood placed into each blood culture bottle. For adults the recommended volume of blood is 20 ml per venipuncture equally divided into the aerobic and anaerobic bottle (10 ml per bottle). For infants and younger children, the volume of blood drawn should be no more than 1% of the patient s total blood volume. The greater the volume of blood added to the blood culture bottle, the better the chance is of isolating pathogenic bacteria from the specimen. Two commonly used manufacturers of blood culture bottles are Becton, Dickinson and Company (BD) and biomérieux. The volumes recommended by each manufacturer follow. Becton, Dickinson and Company (BD) o Adult: 8-10 ml blood per bottle o Pediatric: ml per bottle depending on age/weight biomérieux o Adult: up to 10 ml per bottle o Pediatric: up to 4 ml depending on age/weight Other important aspects to remember regarding blood volume collected for blood culture include the following. Use the laboratory policy on maximum allowable amount of blood drawn at any one time from an infant/child. Laboratories should have a chart listing weight and allowable blood volume to be removed per venipuncture. Attempt to collect the maximum amount of blood to assure the highest quality specimen for culture. For adults, it is recommended to add a minimum of 10 ml of blood to each bottle. Always read and follow the manufacturer s instructions. Instructions may vary over time with a single manufacturer, or different blood culture bottle manufacturers may have completely different instructions. Preanalytical Variable 4: Distribution of blood between aerobic and anaerobic bottles Studies recommend that blood be added to both the aerobic and anaerobic bottles with each blood culture request. Some bacteria grow best in the presence of oxygen (aerobic) and other bacteria grow best when no oxygen is present (anaerobic). 7

8 If less than the optimal amount of blood is collected, most manufacturers will advise the phlebotomist to add the recommended volume to the aerobic bottle first; then to add the remaining blood into the anaerobic bottle. Some laboratories may decide to use only aerobic bottles for blood culture. If this is the case, the recommended amount of blood should be added to two aerobic bottles with each collection. Preanalytical Variable 5: Disinfection of skin It is normal for the skin to have bacteria and fungi. This is called normal flora and these bacteria and fungi are thought to provide protective benefits by secreting substances that prevent pathogenic bacteria from growing. The following bacteria are commonly found as normal flora on the skin: Staphylococcus epidermidis, Streptococcus pyogenes, Staphylococcus aureus, and Mycobacteria spp. Candida spp. are the most common fungi normal flora on the skin. The normal flora on the skin can sometimes cause sepsis, especially in individuals with compromised immune systems. This includes but is not limited to organ/bone marrow/stem cell transplant patients, the elderly, newborns, and individuals with chronic illnesses. Prior to the venipuncture for a blood culture, the patient s skin must be disinfected to minimize the chance of the normal flora contaminating the blood specimen. The most commonly used skin disinfection substances are povidone-iodine and chlorhexidine gluconate. Both disinfect equally well. Frepp /Sepp is a commonly used brand of povidone-iodine and isopropyl alcohol, and ChloraPrep is a commonly used brand of chlorhexidine gluconate and isopropyl alcohol. Manufacturer s instructions (current at the time of publication of this course) for the use of each follow. Note: The use of povidone-iodine alone (such as Betadine pads) is not as effective as its use with isopropyl alcohol. If for some reason iodine alone must be used, tincture of iodine (2% iodine and 2% potassium iodide in 47% ethyl alcohol) is a better skin disinfectant. Povidone-iodine: Frepp /Sepp There are two steps when using the Frepp /Sepp preparation. Step 1: Frepp : The Frepp is a sponge with plastic wings that contains an ampule of 70% isopropyl alcohol. 1. Squeeze the wings of the sponge together to break the ampule containing the alcohol. 8

9 2. Holding the sponge by the wings, press the sponge on the skin until the liquid alcohol appears. 3. Gently rub the sponge back and forth over the skin for 30 seconds. Gentle friction is created by going back and forth with the sponge, lifting up and removing dead cells, which helps disinfect the area 4. Allow to dry until skin is no longer wet. This will take at least one minute, maybe longer. Step 2: Sepp : The Sepp is 10% povidone-iodine in a glass ampule inside another ampule with a cotton gauze tip. 1. Squeeze the outer ampule until the inner ampule breaks, releasing povidone-iodine to the tip of the cotton gauze. 2. Apply povidone iodine to the venipuncture site starting at the center and moving outward in concentric circles to the periphery as shown below. 3. Allow the povidone-iodine to dry. This will take at least one minute, maybe longer. 4. Collect the blood specimens for blood culture. 5. After the blood collection is complete, use alcohol wipe to remove the povidone-iodine solution from the skin. Chlorhexidine: ChloraPrep Use of the chlorhexidine/isopropyl alcohol preparation requires only one step. 1. Chlorhexidine preparations such as ChloraPrep are long-handled sponges with wings. The handle of the preparation contains 2% chlorhexidine gluconate and 70% isopropyl alcohol. The wings of sponge are squeezed together to break the ampule containing the chlorhexidine. 9

10 2. Holding the sponge by the wings, press the sponge on the skin until liquid appears. 3. Gently rub back and forth over the skin for 30 seconds 4. Allow the solution to dry until skin is no longer wet. This will take at least one minute, maybe longer. Pros and Cons of Two-Step and One-Step Methods 70% Isopropyl Alcohol and 10% Povidone Iodine Pros Can be used on individuals of all ages (except those with iodine allergies) 2% Chlorhexidine Gluconate and 70% Isopropyl Alcohol Less time consuming as only one step requires drying time Not associated with allergic reactions so skin does not need to be cleansed following the blood collection Improved compliance with procedure as only one step that requires drying time Improved procedure compliance translates into fewer contaminated blood culture specimens Cons Iodine is associated with allergic reactions and cannot be used on some individuals Must be cleansed from the skin following blood collection More time consuming as there are two steps where drying time is required Cannot be used on infants less than two months of age Other Preanalytical Variables Following are other preanalytical variables that may affect the quality of blood culture specimen collection. Arterial blood is not recommended. Many studies have documented higher rates of blood culture contamination when arterial intravascular access devices are used for specimen collection. Therefore, blood for cultures should only be collected from indwelling arterial intravascular devices when no venipuncture sites are available. Specimens should be received in the lab within two hours of collection. Specimens should not be refrigerated or frozen. Specimens should be kept at room temperature. BLOOD CULTURE BOTTLES Blood culture bottles contain a nutrient broth to enable bacterial growth and an anticoagulant to prevent the blood from clotting. There are two basic types of blood culture bottles those with long necks and those with short necks. 10

11 Long neck Short neck Blood culture bottles have different color caps to distinguish: aerobic from anaerobic, pediatric from adult, and the presence of other substances such as o resins/activated charcoal to absorb any antibiotics in the patient s blood o supplemental enrichment media for bacteria such as Mycobacteria Blood culture bottles draw blood using a vacuum but unlike evacuated venipuncture tubes, the bottles can be easily overfilled. Overfilled bottles can lead to false positive test results. Therefore, during specimen collection, the bottles must be observed to assure they are filled only to the volume marker shown on the bottle label. The nutrient broth in the bottle should not come in contact with the needle that is entered into the patient s vein. Therefore, the bottles must sit upright when blood is being added to them. This requires the use of a winged infusion set or syringe for specimen collection. Filling blood culture bottles Blood is added to the bottles using one of the following methods. Direct draw of blood into the bottles using an winged infusion set (butterfly) and tube holder or adapter cap Collection of blood into a syringe then a transfer of blood to bottle using a blood transfer device 11

12 Filling blood culture bottles using adapter caps The long neck blood culture bottles are designed for use with the regular tube holder ( adapter ) used for collection of blood into evacuated tubes. Blood culture bottles with short necks have a special adapter cap sized to fit the bottle top. If needed, an insert is available that allows for the collection of blood into regular evacuated tubes after blood culture bottles have been filled. Both adapters work the same. The tube holder or adapter cap is attached to the luer connector of a winged infusion set (butterfly). Luer connector Venipuncture is performed per standard operating procedures using the winged infusion set. The blood culture bottle is inserted into the tube holder or adapter cap and blood is allowed to flow into the bottle until the fill to line is reached. The bottles must sit upright while blood is entering into them. Filling blood culture bottles using a syringe If long neck bottles are used, the venipuncture can be performed using a syringe to collect blood for a blood culture. However, per the Bloodborne Pathogens Standard and the Needlestick Safety and Prevention Act (both federal laws) the needle on the 12

13 syringe cannot be directly inserted into the stopper of the blood culture bottle. This technique presents too great a risk for an accidental needlestick. Following is the approved technique for transferring blood from a syringe to a blood culture bottle. 1. After venipuncture is completed using a syringe, activate the safe needle device and remove the needle. 2. Use a transfer device to transfer blood from the syringe to the bottle. A transfer device looks like a tube holder (adapter) but it has a needle inside of it. 3. The syringe is attached to the luer end of the transfer device and the blood culture bottle is inserted into the transfer device (where the red stoppered tube appears in this picture). Blood enters the bottle from the syringe. 4. Allow the blood to fill the aerobic blood culture bottle to the fill to line. Remove the bottle, insert the anaerobic bottle, and add blood to the fill to line. 5. When the blood culture bottles have been filled, discard the syringe and blood transfer device as a unit; i.e., do not remove the syringe from the blood transfer device. 6. Gently mix the blood with the culture fluid. 13

14 BLOOD CULTURE SPECIMEN COLLECTION PROCEDURE Following is the recommended procedure for collecting blood culture specimens. This procedure incorporates some information already provided. Equipment Needed Gloves Tourniquet Alcohol wipes Gauze Bandage/Coban wrap Winged infusion set (butterfly) or syringe/safety needle/transfer device Blood culture bottles Disinfection kit (povidone iodine/isopropyl alcohol or chlorhexidine gluconate/isopropyl alcohol) Tube holder, if using long neck blood culture bottles; adapter cap if using short neck bottles Biohazard waste container Procedure 1. Blood cultures are always collected first in the order of draw before any other laboratory tube types. 2. Identify the patient per your facility protocol. 3. Explain the procedure to the patient. 4. Wash your hands per your facility protocol. 5. Gather all needed equipment and items. 6. Don gloves. 7. Tie a tourniquet on the arm and locate the venipuncture site. Note a landmark by the site as you will not be able to repalpate the venipuncture site. Repalpation of the site even with a prepped finger can increase the chance of contamination of the blood culture specimen. 8. Release the tourniquet. You do not want to leave the tourniquet on during the disinfection process as this may take more than two minutes, making it uncomfortable for the patient. In addition, if you are collecting blood for other laboratory tests, it may result in inaccurate patient test results. 9. Disinfect the skin using either the two-step or one-step method as previously discussed. 10. Allow each step to dry. Do not blot, wipe, fan, or blow on the site. Any of these can result in contamination of the blood culture specimen. 11. While site is drying, remove the protective caps on the blood culture bottles and cleanse the septum with a 70% alcohol wipe. Use a separate wipe for each bottle. Do not use iodine or Betadine as this can disrupt the integrity of the rubber stopper. 14

15 12. If. you are using a winged infusion set you are using a syringe Then. a) Connect the blood culture bottle adapter cap to the luer connector of the infusion set. b) Retie the tourniquet. c) Do not repalpate the cleansed venipuncture site. d) Perform the venipuncture. e) Place the adapter cap on the aerobic bottle and push the needle through the septum of the bottle. f) Keep the bottle in an upright position. Blood culture liquid should not come into contact with the winged infusion set tubing or needle. g) Using the fill indicator line on the bottle label, collect the appropriate amount of blood in the aerobic bottle. h) Remove the aerobic bottle from the adapter cap and repeat the procedure for the anaerobic bottle. i) Gently mix the blood with the culture fluid. j) Collect other lab tests if needed. k) Release the tourniquet and remove the needle from the patient. l) Provide appropriate post-puncture care for the patient. a) Attach the safe needle device to the syringe. b) Retie the tourniquet. c) Do not repalpate the cleansed venipuncture site. d) Perform the venipuncture. e) After venipuncture is completed, activate the safe needle device and remove the needle. f) Release the tourniquet. g) Provide appropriate post-puncture care for the patient. h) Use a transfer device to transfer blood from the syringe to the bottle. i) Allow the blood to fill the aerobic blood culture bottle to the fill to line. j) Remove the bottle, insert the anaerobic bottle, and add blood to the fill to line. k) When the blood culture bottles have been filled, discard the syringe and blood transfer device as a unit; i.e., do not remove the syringe from the blood transfer device. l) Gently mix the blood with the culture fluid. 13. Appropriately discard used equipment. 14. Label the blood culture bottles per facility protocol. Do not place the label over the bottle bar codes. 15

16 15. Remove gloves and wash hands. Evacuated Tubes for Blood Culture Specimen Collection In certain circumstances, blood may be collected into evacuated tubes for blood cultures. Two tube types are available and they both have yellow stoppers. The labels of the tubes are clearly marked (as indicated below) and should not be confused with yellow stopper ACD solution A and ACD solution B evacuated tubes. Site preparation for collection of blood into evacuated tubes for blood culture is the same as that used for blood culture bottles. The tubes are collected first in the order of draw before any other laboratory tube types. The stoppers of the tubes must be cleansed as per the procedure for blood culture bottles. Following collection, the tubes should be gently inverted eight (8) times to assure the blood is thoroughly mixed with the additives. Isolator Tubes The Isolator tube is most frequently used when the cause of sepsis is thought to be a yeast/fungus, or acid fast bacteria species such as Mycobacteria. These microorganisms often live inside of red blood cells or white blood cells. Isolator evacuated tubes are sterile, glass, have a yellow stopper, and contain saponin, polypropylene glycol, and sodium polyanethol sulfonate (SPS). Saponin lyses the red and white blood cells, releasing any microorganisms inside them thus increasing the chance they will grow in culture. SPS is an anticoagulant with other properties useful for culture of blood. The polypropylene glycol is a stabilizing agent. Two tube sizes are available: 10 ml and 1.5 ml. The 1.5 ml tubes are for pediatric use only. To increase the likelihood of isolation of microorganisms, a minimum of 7.0 ml of blood must be collected into the 10 ml tube; a minimum of 1.0 ml of blood must be collected into the 1.5 ml tube. Collection of adequate volumes of blood is very important when Isolator tubes are used. SPS Tubes The SPS evacuated tubes are sterile, glass, have a yellow stopper, and contain 1.7 ml of sodium polyanethol sulfonate (SPS). The tube draws 8.3 ml of blood. As with the Isolator tube, SPS serves as an anticoagulant. SPS tubes are most often used when blood culture bottles or Isolator tubes are not available at the time of collection. Blood Culture Specimen Rejection Criteria Blood culture specimens may be rejected by the laboratory for the following reasons: Incorrectly labeled or unlabeled bottles/tubes Broken, damaged, or leaking bottles/tubes 16

17 Bottles/tubes containing blood clots Tubes containing anticoagulants other than SPS BLOOD CULTURES IN THE LAB Once blood culture specimens reach the laboratory, they are placed in an automated instrument for incubation. The instrument continuously monitors the bottles for the production of carbon dioxide (CO 2 ), which indicates bacterial/fungal growth. CO 2 is usually detected between 13 hours to 20 hours of incubation. When a blood culture specimen has been determined to have bacterial/fungal growth, an aliquot of the blood/culture media is removed and placed on agar culture plates. When bacteria/yeast grows on the plates, the clinical laboratory scientist performs biochemical testing to identify the type of bacteria present (e.g. Staphylococcus aureus, Escherichia coli, etc.). Once the identity of the bacteria is known, tests are performed to determine the most appropriate antibiotic to use to treat the infection. BLOOD CULTURE CONTAMINATION A contaminated blood culture occurs when the bacteria found to be growing in the culture are from the patient s skin and are not the cause of the patient s illness. This is called a false positive or a contaminated blood culture. Clinical laboratory scientists and physicians use certain clinical and laboratory guidelines and information to determine if a microorganism isolated from a blood culture is a contaminant or a cause of sepsis. Future discussion of this is beyond the scope of this course. The most common cause of blood culture contamination is the failure of the healthcare professional to adhere to aseptic technique when collecting the specimen. Many individuals collecting specimens are rushed, and they fail to wait for the antiseptic to dry. Studies have shown that use of trained phlebotomists to collect blood cultures rather than random nursing personnel, medical students, resident physicians, and nondegreed nursing assistants reduces the blood culture contamination rate. Trained phlebotomists have been shown to adhere more consistently to strict antiseptic technique. Other causes of blood culture contamination include the antiseptic agent itself and the collection of specimens from indwelling intravenous lines. Blood culture contamination is a major concern to physicians, patients, clinical laboratory scientists, and phlebotomists as it causes or delays appropriate treatment and significantly increases hospital costs. Most blood culture contamination comes from bacteria on the patient s skin. Unfortunately, however, these bacteria can also cause septicemia. Therefore, when the patient s blood culture results are positive, the doctor must initiate treatment as if the patient has septicemia when in fact it may be contamination. Studies show that treating a patient for a false positive blood culture: 17

18 Extends his/her hospital stay by as much as 4.5 days, and Increases the cost of treatment by as much as $8,700 from increased laboratory costs, increased pharmacy costs, and increased length of hospital stay. The following organizations strongly recommend or require the monitoring of blood culture contamination rates (percentages) to ensure that phlebotomists are following best practices in blood culture collection. The Joint Commission an organization that inspects and accredits healthcare organizations The College of American Pathologists (CAP) an organization that inspects and accredits clinical laboratories The American Society of Microbiology an organization that provides best practice guidelines to improve health and economic well being Therefore, almost all laboratories measure blood culture contamination rates on a monthly basis as a performance improvement monitor. The blood culture contamination rate is calculated for each individual. Following are examples of how contamination rates are determined. Healthcare Professional A collected 50 blood culture specimens in April 2012 and five (5) were determined to be false positives due to contamination. This equals 10% blood culture contamination rate. Healthcare Professional B collected 102 blood culture specimens in September 2012 and two (2) were determined to be false positives due to contamination. This equals a 1.9% blood culture contamination rate. The accepted threshold of contamination is 3% but most laboratories tighten the threshold to 2 2.5%. All performance improvement monitors must have a plan of action should the acceptable threshold be exceeded. For blood culture contamination, documented retraining is indicated when a phlebotomist (or other healthcare provider) exceeds the acceptable number of contaminated blood cultures. In the examples above if the laboratory uses an accepted threshold of 2.5%, Healthcare Professional A has exceeded this threshold, and documented retraining is indicated. CONCLUSION If not aggressively treated, sepsis can lead to significant rates of morbidity and mortality. Of utmost importance is the proper collection of blood cultures for diagnosis and treatment of the bacterial/fungal infection. Phlebotomists and other healthcare professionals who collect blood culture specimens play a vital role in guaranteeing preanalytical variables are minimalized to ensure accurate and reliable test results. REFERENCES Bacterial Sepsis. Downloaded 5/7/2009 BacT/ALERT Blood Culture Collection. Downloaded 5/5/

19 BD BACTEC Blood Culture Media and Collection. Downloaded 5/5/2009 ChloraPrep. Downloaded 5/7/2009 Principles and Procedures for Blood Cultures; Approved Guideline. Clinical and Laboratory Standards Institute. May 2007 Surviving Sepsis Taming a Deadly Immune Response. National Institutes of Health August. newsinhealth.nih.gov/august Accessed 14 March 2014 Systemic Inflammatory Response Syndrome; Medscape Reference, www. Downloaded 10/3/2012 TEST QUESTIONS Sepsis and Blood Culture Specimen Collection # Directions: Answer sheets: Read the instructions to assure you correctly complete the answer sheets. Online: Log in to your User Account on the NCCT website o NOTE: If the online test questions differ from the course test that follows the reading material, the CE course you are using is outdated or the question has been revised since you downloaded it. The online question is the most current and it should be answered accordingly. Select the response that best completes each sentence or answers each question from the information presented in the course. If you are having difficulty answering a question, go to and select Forms/Documents. Then select CE Updates and Revisions to see if course content and/or a test questions have been revised. If you do not have access to the internet, call Customer Service at The presence of bacteria in the blood is called. a. bacteremia b. fungemia c. septicemia d. SIRS 2. Most cases of sepsis arise from which one of the following types of infection? a. Abdominal b. Bronchopulmonary c. Urinary tract d. Wound 19

20 3. Which one of the following is NOT a preanalytical variable for blood culture specimen collection? a. Disinfection of skin prior to collection b. Volume of culture media in bottles c. Number of culture bottles collected d. Volume of blood added to bottles 4. Studies have shown that the best chance of identifying pathogenic bacteria occurs when how many sets of blood cultures are collected? a. One b. Two c. Three d. Four 5. For adults, which is the minimum volume of blood recommended to be added to one blood culture bottle? a. 20 ml b. 15 ml c. 10 ml d. 5 ml 6. If you are only able to collect 15 ml of blood, how should you distribute it between the aerobic and anaerobic blood culture bottles? a. Put all 15 ml into aerobic bottle b. Put 7.5 ml in aerobic bottle and 7.5 ml in anaerobic bottle c. Put all 15 ml into anaerobic bottle d. Put 10 ml into aerobic bottle and 5 ml into anaerobic bottle 7. The povidone-iodine/isopropyl alcohol prep differs from the chlorhexidine prep in all of the following ways EXCEPT. a. it is a two-step method b. it disinfects better c. it can be used on patients of all ages d. it is a longer procedure 8. Which of the following is TRUE regarding skin disinfection? a. The sponge must be firmly rubbed back and forth on the skin. b. It is OK to repalpate the disinfected site prior to venipuncture. c. Chlorhexidine must be removed with an alcohol wipe after the venipuncture. d. The disinfecting agent must be allowed to dry before the venipuncture. 20

21 9. Blood culture specimens should be refrigerated if they cannot promptly be delivered to the lab. a. True b. False 10. The vacuum in blood culture bottles will draw in the correct amount of blood. a. True b. False 11. Why do blood cultures have to be drawn using a winged infusion set or a syringe? a. Patients having blood cultures drawn always have small delicate veins, so a winged infusion set is needed. b. The winged infusion set needle can easily be pushed into the top of the blood culture bottle. c. The winged infusion set needle is the only needle that will fit into the bottle adapter. d. The bottle must be upright during collection, so the culture media does not come into contact with the needle. 12. When would a blood transfer device be used? a. When transferring blood from a syringe into a wide neck blood culture bottle b. When transferring blood from a syringe into a long neck blood culture bottle c. When transferring blood from a red top tube into a long neck blood culture bottle d. When transferring blood from a lavender top tube into a short neck blood culture bottle 13. Why is it important to minimize the number of contaminated blood cultures? a. It looks bad for the laboratory b. It increases the patient's hospital stay and charges c. It is required by lab accrediting agencies d. It makes more work for the pharmacists 14. What is the generally accepted threshold for blood culture contamination? a. 1% b. 2% c. 3% d. 4% 21

22 15. How are the tops of the blood culture bottles cleansed? a. With a separate alcohol wipe for each bottle b. With a separate iodine swab for each bottle c. With the sponge used to cleanse the skin d. With nothing; the bottle tops are already sterile 16. To speed up drying of the skin antiseptic, it is permissible to blow on or fan the site. a. True b. False 17. Which of the following is an additive in both of the yellow stopper tubes that are sometimes used for blood cultures? a. Calcium oxalate b. EDTA c. Sodium citrate d. Sodium polyanethol sulfonate 18. Which of the following would be a reason to reject a collected blood culture specimen? a. Adult bottle with 0.6 ml of blood b. Bottle with clotted blood c. Unlabeled bottle d. All responses are reasons for rejection *End of Test* 22

23 P.A.C.E. Course Evaluation NCCT 7007 College Boulevard Suite 385 Overland Park, KS Directions: Please let us know whether this CE Course met your expectations by answering the following questions. Your feedback helps us to make our products better for you! Course Title: Sepsis and Blood Culture Specimen Collection Course #: OBJECTIVES Yes No Yes No 1. Did you meet the objectives while reading this CE course? 2. Did the test measure what you learned? COURSE CONTENT Yes No Yes No Yes No 3. Were you satisfied with this course? 4. Was the CE course organized and useful for learning? 5. Was this CE course written at the right level for the practicing professional? VALUE Yes No Yes No Maybe 6. Did you learn anything new? 7. Did you learn anything you might use at work? What can NCCT do to make the CE courses better for you? What would you like to learn about in the future? Please list specific topics! *Please include this evaluation with your answer sheet.* 23