Policy Statement:

• The Hemoccult occult blood slide is only used for screening stool samples for the presence of fecal occult blood. The Hemoccult occult blood slide is to be used only for fecal occult blood, other body fluids are not suitable for testing for the presence of occult blood using the Hemoccult kit.  Stool occult testing, using the Hemoccult  slides, will be performed in the laboratory and in designated Point-Of-Care-Testing areas.  All other departments in the hospital will collect specimens for occult blood testing but will submit to laboratory for testing.

PRINCIPLE OF MEASUREMENT:

• Hemoccult is composed of guaiac impregnated paper enclosed in a cardboard frame which permits sample application to one side, and development and interpretation on the reverse side. The process involves placing two specimens, collected from each of three successive evacuations, onto the guaiac paper. Hemoccult  is based on the oxidation of guaiac by hydrogen peroxide to a blue colored compound. The heme portion of hemoglobin, if present in the fecal specimen, has peroxide activity which catalyzes the oxidation of alpha guaiaconic acid (active component of the guaiac paper) by hydrogen peroxide  (active component of the developer) to form a highly conjugated blue quinone compound.

Equipment and Materials:

• Stool collection device (outpatients can obtain from laboratory)
• Applicator sticks
• Collection container

REAGENTS:

• Hemoccult slide.  Store at room temperature, in a dry place.  Protect from heat, direct sunlight, and other strong light sources.  The color of the non-reacted test area should be cream to light yellow.  Slide packs with test areas that have turned blue or blue-green should not be used. 
• Hemoccult developer.  Stabilized hydrogen peroxide in aqueous methanol.  Store the developer in a dry place, away from heat, direct light, and open flame.  Keep bottle tightly closed when not in use.  (See reagent handling).  The developer is not to be distributed to patients.

CONTROLS:

• Controls are done with each test and are provided on each card.

SPECIMEN:

• Patient preparation recommended 7 days prior to testing.
  • Avoid aspirin or other non-steroid anti-inflammatory drugs, seven days prior to testing.
• Recommended 72 hours prior to testing and continuing throughout the testing:
  • Do not eat read meat, turnips, horseradish or take medications containing aspirin or Vitamin C.
  • Eat only small amounts of chicken, canned tuna, peanuts, popcorn or bran cereal.
  • Eat plenty of vegetables (raw or cooked), lettuce, spinach, corn, prunes, grapes, plums and apples.

Specimen  Collection:

For outpatients: instructions by manufacture are provide together with proper mail instructions, and envelopes.

1. Collect stool specimen in a clean container or from the toilet paper.  Only a very small amount of specimen, sparingly applied, to the slide is required.
2. Open the front flap of the Hemoccult slide, and apply a thin smear of stool sample in box A. Reuse applicator to obtain a second sample from a different part of the stool specimen. Apply a thin smear inside Box B.  Do not obtain a specimen from the toilet water, since cleaning chemicals may cause false positive results.
3. On subsequent bowel movements, repeat above steps on additional slides. Because of the nonhomogeneity of the stool, it is recommended that the test be performed on three consecutive evacuations.
4. The completed slide can be developed immediately or may be stored in a dry place for up to 14 days.
5. Label the slide with the patient’s full name, medical record number, date and time of collection.
6. Patient specimens and all material in contact with them should be handled as biohazards and should be disposed of using proper precautions.

•  Specimen Collection Notes:
  • Patients with bleeding disorders not related to gastrointestinal bleeding, or female patients with menstrual bleeding should not be tested while such conditions persist.
  • Other factors which affect the test are bleeding hemorrhoids or open cuts on hands.
  • Use only Hemoccult slides for occult blood testing – all other slides submitted will NOT be tested.

Storage Requirements:

All reagents need to be stored at room temperature and are stable until the manufacturer’s expiration date. 

QUALITY CONTROL:

• The reactivity of the Hemoccult test can be checked by using the Hemoccult internal controls included in the test pack.  Use of the control verifies the following: 1) the guaiac paper and/or the developer are performing correctly; 2) the testing procedure has been performed correctly; and 3) the person performing the testing is able to differentiate between a negative and positive result.
• Each patient slide tested will be controlled using the hemoccult performance monitors on each slide. 
• The control results will be documented in the LIS when performed by the laboratory.  The control results will be documented on the Occult blood form when performed by Point-Of-Care certified personnel
• QC Procedure
  • Develop the patient sample as outlined in the procedure for patient testing.
  • Apply one or two drops only of Hemoccult developer between the positive and negative performance monitor areas.
  • Read results within 60 seconds..
• QC Interpretation
  • If the slide and developer are functional, a blue color will appear in the positive performance monitor area and no blue color will appear in the negative performance monitor area.
  • Neither the intensity nor the shade of the blue from the positive performance monitor should be used as a reference for the appearance of positive test results. 
  • Any blue color originating from the positive performance monitor area should be ignored when reading the patient sample test area.
  • If the performance monitors fail to give appropriate results the patient test slide must not be used to interpret patient test results.  The slide must be discarded and a new sample obtained.  Contact the laboratory for new slides.  Corrective action measures must be taken and documented in the Occult Blood Corrective action section of this policy.

 IMPLEMENTATION:

Procedure:

1. Using the applicator provided apply a very thin smear of stool in box A.
2. Reuse the applicator and apply a sample from a different part of the stool specimen to Box B.
3. Allow the specimen to air dry, then close the cover. If testing immediately, wait 3-5 minutes before developing.
4. Open perforated window on the back of the slide.
5. Apply two drops of Hemoccult Developer to the backside of boxes A and B.
6. Read results within 60 seconds. Any trace of blue on or at the edge of the smear is positive for occult blood. Negative result should be read right at 60 seconds.  Positive result can be read as soon as blue color appears in the test area.
7. Apply one drop of Hemoccult Developer between the positive and negative Performance Monitor area. Read results of the quality controls within 10 seconds.

DOCUMENTATION:

• Fill in the Fecal Occult Blood Test sticker located on the log sheet. Put patient’s bar code sticker on the left side. Tear off the right side of the sticker and place on the patient’s chart. The left side of the sticker stays on the log.

INTERPRETATION: 

NORMAL VALUES:

Reference Ranges: Test results from normal adults will be negative.  Normal blood loss in adult humans is approximately 2 –3 mL/100 grams of feces, a concentration below the sensitivity of this test. Hemoccult will detect 10 mg of hemoglobin per gram of homogenized fecal material. Clinical studies illustrate that the guaiac impregnated slide tests yield a positive testing range of 3-5% in screening programs. The false positive rate was between 1-2% during controlled conditions (diet, medical supervision, etc.)

SPECIAL CONSIDERATIONS, PRECAUTIONS

PROCEDURE NOTES:

• The Hemoccult test result must not be considered as conclusive evidence of gastrointestinal bleeding without other supportive data from radiographs and/or proctosigmoidoscopic examinations.
• False positives may be encountered in certain circumstances. Ingestion of read meat or preparations containing hemoglobin and other peroxidase or peroxidase-like substances.  Certain medications, including aspirin, phenylbutazone, iron preparations and others, may cause gastrointestinal bleeding that might be confused with pathological conditions. 
• Ingestion of large quantities of Vitamin C may give false negative results.
• The Hemoccult occult slide is to be used for fecal samples only.

REAGENT HANDLING:

• Hemoccult developer is poisonous and flammable.  DO NOT INGEST OR PLACE IN EYES. May cause blindness, or be fatal if swallowed. Avoid contract with skin, eyes or easily oxidized material.  If contact should occur, rinse area promptly with large amounts of water.

 REFERENCES:

• Manufacturer product insert, Hemoccult  slide test:  Beckman Coulter, Inc. , Fullerton, California.                 
• Tietz, Norbert W., Fundamentals of Clinical Chemistry, W.B. Sanders, Co., Philadelphia, 1987.

 Composed:  11/11/03

 Revised 7/27/05                                                    Review Date: 7/27/07