HARBOR-UCLA MEDICAL CENTER Torrance, California DEPARTMENT OF EMERGENCY MEDICINE POLICY AND PROCEDURE MANUAL

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Ralf Clarke
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1 25.5 Point of Care Testing Occult Blood Testing by Physicians POLICY The Hemoccult test is a rapid convenient and virtually odorless qualitative method for detecting fecal occult blood. It is used as a diagnostic aid during physical examinations to screen for gastrointestinal bleeding. It is useful in evaluating patients with suspected iron deficiency anemia, peptic ulcer disease, ulcerative colitis, colorectal cancer, and other illnesses. It is not a specific diagnostic test for colorectal cancer. Principle: The Hemoccult test is a simplified and standardized variation of the laboratory guaiac procedure for occult blood. The test card contains a specially prepared stabilized guaiac paper and is ready for use without additional preparation. A stool sample is applied directly to the guaiac paper on the slide. The test is then developed by applying a hydrogen peroxide solution to the back of the smeared sample. If blood is present in the stool sample, a blue color will appear on the edge of the fecal smear within 60 seconds after adding the developer. The Hemoccult test reaction is based upon the oxidation of guaiac by hydrogen peroxide to a blue color. If blood is present in a stool sample the hemoglobin will be released. The released hemoglobin possesses peroxidase activity where the Heme portion of the hemoglobin reacts with the Hemoccult test by catalyzing the oxidation of alpha guiaconic acid by hydrogen peroxide to form a highly conjugated blue colored quinone compound. Specimen Collection: The specimen may be obtained during a rectal exam from a gloved finger or from a specimen submitted by the patient.

2 Reagents and Equipment: Procedure: 1. Hemoccult slides - store at room temperature and protect from light. The slides are stable up to the manufacturers expiration date. 2. Hemoccult Developer - store at room temperature in a clean dry area. The developer is stable up to the manufacturers expiration date. 1. Gather required equipment and verify expiration date for developer and slide. 2. Explain procedure to patient or parent. 3. Using universal precautions and following package insert instructions, collect a small stool specimen on the end of an applicator stick. Alternate - During a rectal exam a small amount of fecal material can be obtained from a gloved finger. 4. Apply a thin smear of fecal material to box A and obtain another sample from a different part of the specimen and apply it to box B. If the specimen is from a rectal exam both box A and B can be prepared from the glove. 5. Close the cover 6. Open the flap on the back of the slide and apply two drops of the developer directly over the smear. 7. Read the results within 60 seconds. Any trace of blue on or at the edge of the smear is positive for occult blood.

3 Quality Control: A positive and negative control is run with each patient (test card). The control is run after the patient test area has been developed. 1. Apply one drop of Hemoccult developer between the positive and negative performance monitor areas. 2. Read within 10 seconds a. Positive Performance Monitor Area - blue coloration b. Negative Performance Monitor Area - no blue color 3. If the controls do not perform as described above, disregard the test results and call Smith Kline Diagnostics Technical Support for assistance. Reporting Results: 1. Negative - No detectable blue color on or near the edge of the smear. 2. Positive - any trace of blue on or at the edge of the smear. Considerations: 1. Occasionally a light blue discoloration may be noticed on the guaiac paper. This discoloration does not affect the tests accuracy or their performance when it is developed or interpreted according to the recommended procedure. When developer is added to the fecal smear on a discolored slide, the blue background may migrate outward. A blue ring forms at the edge of the wetted circle, leaving the guaiac paper around the fecal smear off white in color. Interpretation is the same as described in reporting results.

4 25.5 Point of Care Testing Occult Blood Testing by Physicians continued 2. Some fecal samples have a high bile content which causes them to appear green. A distinct green color appearing at or on the edge of the sample within 60 seconds after adding the developer should be interpreted as negative. However, a blue or blue-green color should be interpreted as positive. 3. Fecal samples should be evaluated with caution if hematuria, hemorrhoids, or obvious rectal bleeding is present, or during the first three days after a menstrual period. Reporting Results: Emergency medicine and pediatric residents receive instruction in the performance of fecal occult blood measurement in lecture format and must also read the department policy on the subject. A test is then administered and each resident must score 100%. Detection of blue colorblindness is based on self-reporting by each resident. The competency exam asks the examinee if he or she is blue colorblind. Anyone answering yes to this question will be furthered tested individually to ascertain if that person can still detect the color blue. Anyone failing to demonstrate the ability to detect blue color on the hemoccult card will be prohibited from individually interpreting the fecal occult blood test. After successfully passing the exam, each resident performs the test once while supervised by an individual already certified. Only then are they permitted to test stool for occult blood independently. A record of successfully completing the training and testing process is kept by the chief resident. Residents from outside services rotating through the emergency department will receive an orientation packet containing the fecal occult blood testing policy. After reviewing the policy, a test is administered and each resident must score 100%. After successfully passing the exam, each resident performs the test once while supervised by an individual already certified. Only then are they permitted to test stool for occult blood independently. A record of successfully completing the training and testing process is kept by the chief resident.

5 RESIDENT EXAM FOR FECAL OCCULT BLOOD PROCEDURE 1. What color appears on the hemoccult slide when blood is present? 2. Which of the following statements is true? A. If a light blue discoloration is noticed on the slide paper, the slide should be discarded. B. The hemoccult test is not a specific test for colorectal cancer. C. The quality control test is found in the box containing the slides and should be performed once a week. D. A woman's menstrual period has no effect on the outcome of a hemoccult test. 3. When may an emergency medicine or pediatric resident perform stool occult blood testing independently? 4. Are you colorblind with respect to the color blue? Yes No I read and understand the policy on fecal occult blood testing. NAME: DATE: Signature:

6 ANSWERS FECAL OCCULT BLOOD ANSWERS 1. Blue 2. B 3. An emergency medicine or pediatric resident may perform stool occult blood testing independently only after attending a training lecture on the subject, reading the department policy, scoring 100% on the exam, and performing the fecal occult blood test once in the presence of an individual already certified in the procedure. Reviewed: Date: By: Title:

Written By: Joann O Connor Date: 01/27/2017 Effective Date: 02/22/2017 1

Written By: Joann O Connor Date: 01/27/2017 Effective Date: 02/22/2017 1 Department Of Pathology Point of Care Testing POC.516.12 Hemoccult-LBH Version #12 Printed copies are for reference only. Please refer to the electronic copy for the latest version. A. PURPOSE: The Hemoccult