CDOS

Occult Blood, Gastric Fluid

Test Code: 182196

Performing Lab: LabCorp

CPT Code: 82271 001

Test Link (Copy)

Synonym

Blood, Occult

Specimen Type

Gastric fluid

Specimen Container

Sterile leakproof container with screw-cap. Refer to the Microbiology Specimen Collection chart in the Microbiology Appendix.

Volume

5 mL

Patient Prep

Antacid usage within 60 minutes of collection may affect test results. Ascorbic acid (vitamin C) has been shown to cause false negative test results for occult blood. This may also occur with the Occult Blood, Gastric Fluid, test. triction of peroxidase-rich vegetables(turnips, horseradish, artichokes, mushrooms, radishes, broccoli, bean sprouts, cauliflower, apples, oranges, bananas, cantaloupes, grapes), has been recommended for 72 hours prior to guaiac testing, and during testing, to decrease the incidence of false- positives. Therapeutic iron causes false-positives with guaica with guaiac tests in over half of healthy subjects. Alcohol and aspirin, especially together,and other gastric irritants steroids, rauwolfia derivatives, all nonsteroidal anti-inflammatory drugs, colchicine) should also be avoided.

Temperature

Refrigerate

Methodology

Guaiac test it include Colo-Screen (Helena Laboratories), Colo-Rect (Roche Diagnostics), Hema-Chek(Miles Laboratories), Quick- Cult (Laboratory Diagnostics), and Hemoccult II(SmithKline). The peroxidase-like activity of hemoglobin or nonspecific oxidants catalyze the reaction of peroxide and the chromogen orthotolidine to form blue oxidized orthotolidine. New meth- odology, based on heme-derived porphyrin fluorescence, is more expensive (HemoQuant). It detects peroxidase-negative heme-derived porphyrins, peroxidase-positive hemoglobin, and free heme.[13] Immunologic tests have been developed, but enteric degradtion of hemoglobin interferes with immunologic as well as guaiac tests. Immunologic tests do not react ??

Stability

Room Temperature: 24 hours (stability determined by manufacturer or literature reference)
Refrigerated: 5 days (stability determined by manufacturer or literature reference)

Result Code	Result Name	LOINC
182196	Occult Blood, Gastric Fluid	2334-1

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