CLINICAL LABORATORY SERVICES

Transcription

1 13. SPECIMEN COLLECTION AND HANDLING GUIDELINES General guidelines For microbiology investigations the prompt and accurate isolation of infecting agents is directly influenced by the quality of the specimen. With the exception of suspected meningitis it is almost always possible to obtain appropriate specimens before commencing antibiotic therapy. The following points should be adhered to: Collect specimen before administration of antibiotic therapy Specimen should be transported to the laboratory as soon as possible Ensure that the specimen container is clearly labelled with the patient s details Remember that you may be dealing with pathogenic microorganisms and care should be taken while obtaining and handling the specimen (see on NHS Shetland intranet the Infection Control Guidelines) Infection control Wash hands thoroughly or use sanitizer (the latter if hands are visibly clean) before obtaining the specimen and after it has been prepared for collection Gloves should always be worn when handling bodily fluids Do not overfill container Ensure container is securely closed and outside of container is not contaminated by the specimen Place the specimen in a polyethene bag for transport to the laboratory Note: Where the request form is not attached to a polyethene bag, e.g. Virology, a separate biohazard bag should be used (obtained from the laboratory). NB: If you are in any doubt about the most appropriate specimen or container, please contact the laboratory for advice (see contact details).

2 13.3. Procedure for obtaining blood samples from low risk patients a) Personal hygiene: inspect your hands and make sure that any recent cuts or abrasions are covered with a waterproof dressing without visible air holes. Wear gloves if appropriate. Avoid needle pricks, spilling blood and contaminating with blood the outside or rim of the specimen container. Do not lick labels, envelope etc. b) Tray: to reduce the risk of spillage make sure that all the equipment you need is to hand and safely held on a tray preferably in suitable holders or compartments. All parts of the tray should be either disposable, autoclaveable or cleanable by surface disinfectant solution. Ensure this solution is to hand. c) Sarstedt Monovette blood collection system: this is the preferred blood collection system in NHS Shetland and enables a variety of tube types to be used. d) Screw top sample containers: use the appropriate container (see individual laboratory sections). This is to ensure the correct anticoagulant, if required, and minimises the chance of the specimen clotting. e) Closure: ensure that the cap on the container is secure. Leaking containers are dangerous; furthermore if the sample leaks you may have to bleed the patient again. If there is anticoagulant in the container dissolve it in the blood by inverting the tightly closed container slowly several times. f) Needle: dispose of any needle, syringes etc. as a single unit. Keep all this equipment separate from all the other waste and discard it into a container approved and marked for disposal of SHARPS. g) Discards: mediswabs, gloves, cotton wool, and other blood-contaminated materials used for venepuncture should be placed into a clinical waste bin.

3 h) Spillage of blood: if any sharp items, e.g. broken glass, are involved, where possible, use thick, heavy duty gloves, otherwise use ordinary surgical gloves. In the event of broken glass, pick up all fragments carefully with forceps and discard them into a container approved and marked for the disposal of "sharps", never into a plastic bag. Dilute any split blood with 1% Virkon solution or chlorine granules and mop it up with absorbent paper. Put the mopping up material into a yellow biohazard bag, close it securely, e.g. by knotting it, and send it for incineration. Remove the gloves, put them in a yellow plastic bag, close it securely and send for incineration. Then wash your hands. NB: Never attempt to re-sheath a needle. Never leave a needle, or sharp for someone else to clear away, discard it safely Procedure for obtaining blood samples from suspected or known high risk patients. Special precautions are needed for samples that are collected from patients who are at high risk of hepatitis B, C or HIV. a) Additional precautions for obtaining a blood sample from a suspected or known "high risk" patient: blood samples should only be taken by staff experienced in venepuncture. The following precautions MUST be taken: 1. Wear well-fitting surgical gloves and plastic apron. 2. If available, wear safety spectacles. 3. A yellow hazard-warning label must be put on the specimen container. 4. Blood samples should be double bagged and where possible sent in a robust screw-capped container with the cap securely tightened, and sealed in a plastic bag with an integral-sealing strip. 5. The request form, to which a yellow hazard label must be attached, should be placed in the external pocket of the bag. 6. The specimen should be transported in the upright position.

4 b) Disposal of blood contaminated items: all syringes, needles or Monovette systems should be disposed of as a single unit into a sharps bin. Mediswabs, gloves, cotton wool and any spilt blood must be dealt with at once by disinfecting with 1% Virkon solution (10,000 ppm of available chlorine) or chlorine granules. (In collecting and transporting specimens from outpatients, the same precautionary measures must be taken as described above). c) Action to be taken in the event of an accident involving blood or other body fluids from a suspected or known high risk patient: if there is personal injury from a needle prick or cut, the following action should be taken: 1. Make the lesion bleed freely at once to help wash away infection. 2. Wash it immediately and thoroughly with running tap water. 3. Apply a suitable dressing (as provided in first aid boxes). 4. If blood or other body fluid is splashed into the eye, nose or on the lips, wash it away immediately with running tap water. 5. Follow Needle Stick Injury Procedure applicable to your workplace. d) Accidental Exposure to Blood Borne Pathogens i. Procedure: any accident involving the puncture of the skin by a needle or scalpel contaminated with blood from ANY patient, or the spilling of such blood on broken skin must be reported as soon as possible to your superior. The member of staff concerned MUST attend the A&E department immediately. If the accident occurs outside of normal working hours a senior nurse medical team on-call can be contacted through switchboard. ii. Advice: for advice during normal working hours, in the first instance contact Occupational Health on extension Staff at ARI, Medical Microbiology/Virology department are also available for advice. Outside normal working hours you may contact via switchboard. GP surgeries should follow their own standard operating procedures for Accidental Exposure to Blood

5 Borne Pathogens. CLINICAL LABORATORY SERVICES Specimens requirements and protocols Patient instructions for collecting Mid-Stream Urine (MSU) General instructions 1. Collect 20 ml of urine in a sterile specimen container. 2. Transfer urine to a Boricon urine transport container (red top container). 3. Transport to the microbiology laboratory. 4. If unable to collect 20 ml of urine, collect in sterile specimen container (37778) and Transport urine specimens to the microbiology laboratory immediately or refrigerate within 30 minutes. 5. Refrigerated specimens should be delivered to the lab as soon as possible, and may be rejected if not received within 24 hours of collection Midstream clean catch method: Patients should be instructed to wash hands prior to collection and offered exam gloves. Female patients should be instructed to sit on toilet with legs apart and spread labia with one hand. First void in toilet and then, continuing to void, hold specimen container in "midstream" to collect sample. Male patients should be instructed to retract foreskin if uncircumcised. First void in toilet and then, continuing to void, hold specimen container in "midstream" to collect sample Straight catheter: Thoroughly cleanse the urethral opening with soap and water. Rinse area with wet gauze pads. Aseptically insert catheter into the bladder. After discarding initial 15 to 30 ml of urine, collect 20 ml of urine for submission in a Boricon urine transport container.

6 Indwelling catheter: Clamp catheter below port and allow urine to collect in tubing. Disinfect the catheter collection port with 70% alcohol. Use needle and syringe to aseptically collect 20 ml freshly voided urine though catheter port. Transfer to Boricon urine transport container. Do not collect urine from collection bag Ileal conduit: Remove the external device and discard urine within device. Gently cleanse the stoma with 70% alcohol followed by povidoneiodine swab stick (907172). Using sterile technique, insert a double catheter into the cleansed stoma, to a depth beyond the fascial level, and collect the urine into a sterile container. Transfer to Boricon urine transport container. Use of a double catheter helps to minimize contamination of the specimen with skin flora Patient instructions for collecting 24 hour urine Important points It is very important that al urine passed in an exact 24 hour period is collected. Loss of any urine or a collection made for either more or less than 24 hours will invalidate the tests and might lead to an incorrect diagnosis Do not void urine directly into the 24-hour container, but into a suitable clean detergent-free jug and then pour into the 24-hour container. If the container contains acid (used as a preservative) or has a warning label, then care needs to be exercised when adding urine from the collection vessel. Hydrochloric acid causes burns and is irritating to eyes, skin and respiratory system. If it comes in contact with skin, wash the affected area immediately with plenty

7 of water and seek medical advice. Keep out of reach of children. Not to be taken internally would cause severe irritation and damage. The laboratory provides an information leaflet when containers are provided. This should be read carefully. Ensure that the container is labeled with patient s full name and date of birth Instructions for sample collection Empty your bladder at 7am on rising (or at a more convenient time) and throw away the sample. The collection is started after this sample has been passed. Write the start time on the specimen container label. Collect all urine in the container provided on every occasion that it is passed during the following 24 hours and store refrigerated if possible. Empty your bladder at 7am on rising the next morning (or at the more convenient time chosen) and add this sample to the collection. Write the finish time on the container label. Bring the container to the laboratory on the day of completion Incomplete collections If a sample is forgotten or lost down the toilet, then all the urine collected to this point should be thrown away and the collection restarted the following morning. If the incomplete sample is an acid collection, the original container should be returned to the laboratory and a new one requested Patient instructions for collecting Faeces / stool sample

8 General guidelines 1. Submit g in sterile container. 2. Transport time 1 hour. 3. Refrigerate if transport is delayed. 4. Stools are cultured to isolate bacterial causative agents of diarrheal illness; Salmonella, Shigella, Campylobacter, and Shiga toxin producing E. coli. 5. Stools for C. difficile toxin detection must be transported to the laboratory immediately or refrigerated if transport is delayed Instructions for sample collection Label the specimen container with your surname, forename, date of birth. Place plenty of toilet paper in a clean potty of in the toilet bowl. Make sure there is no trace of disinfectant or bleach present, as this will interfere with the test. Faeces (a bowel movement) should then be passed onto the toilet paper. Open the specimen container. Place a sample of the faeces in the specimen container. There is no need to fill the container. Screw the lid firmly back on the container. Note: If you have severe diarrhea or a watery stool, a potty may be needed to collect the initial sample. Place the container in the plastic bag attached to the form and seal the bag. Flush away the remaining paper and faeces. Wash your hands thoroughly with soap and water. Check that the request form details the full name and date of birth of the person providing the sample and add the date and time of the sample collection.

9 The sample should be brought promptly to the laboratory for analysis. A report will be sent to the requesting doctor, usually within 3 working days Patient instructions for collecting for Oral Glucose Tolerance Test Principle The oral glucose tolerance test involves the taking of two blood samples: one when you arrive (fasting 8-14 hours) and one 2 hours after a glucose drink. The oral glucose tolerance test (OGTT} is principally used for diagnosis when. blood glucose levels are equivocal, during pregnancy, or in epidemiological studies. The OGTT should be administered in the morning after at least three days of unrestricted diet (greater than 150 g of carbohydrate daily) and usual physical activity. Recent evidence suggests that a reasonable (30-50g) carbohydrate containing meal should be consumed on the evening before the test. The test should be preceded by an overnight fast of 8-14 hours, during which water may be drunk. Smoking is not permitted during the test. The presence of factors that influence interpretation of the results of the test must be recorded (e.g. medications, inactivity, infection, etc.). After collection of the fasting blood sample, the subject should drink 75 g of anhydrous glucose or 82.5 g of glucose monohydrate (or partial hydrolysates of starch of the equivalent carbohydrate content) in ml of water over the course of 5 minutes. For children, the test load should be 1.75 g of glucose per kg body weight up to a total of 75 g of glucose. Timing of the test is from the beginning of the drink. Blood samples must be collected 2 hours after the test load.

10 Unless the glucose concentration can be determined immediately, the blood sample should be collected in a tube containing sodium fluoride (6 mg per ml whole blood) and immediately centrifuged to separate the plasma; the plasma should be frozen until the glucose concentration can be estimated. For interpretation of results, refer to Table 1. Please to refer to: World Health Organization, Definition, Diagnosis and Classification of Diabetes Mellitus and its Complication. Part 1: Diagnosis and Classification of Diabetes Mellitus. NB: For further specimen requirement and protocols see Lab Tests Online-UK ( Lab Tests Online-UK is supported by The Royal College of pathologists and The Institute of Biomedical Science.