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Test Code 359 Occult Blood, Stool

Specimen Containers and Fixatives

Specimen collection card

Specimen Required

All locations: submit stool sample at room temperature on specimen collection card.

Day(s) and Time(s) Performed

Microbiology

Daily, 24 hours

Reference Values

Negative

Lack of sensitivity to small amounts of blood may fail to detect slower rates of blood loss. Also, blood, if present, may not be distributed uniformly in the specimen. Clinical studies indicate that a daily blood loss of 2-3 mL is the lower limit of abnormality and may indicate gastro-intestinal pathology. Based on using representative specimens with whole blood added, the occult blood method used in the laboratory, can be expected to give a positive result 50% of the time when the equivalent daily blood loss in 2-3 mL.

Since bleeding from gastrointestinal lesions may be intermittent, fecal specimens for testing should be collected from three consecutive bowel movements closely spaced in time. To further increase the probability of detecting occult blood, separate samples should be taken from 2 different sections of each fecal specimen.

Fecal specimens should not be collected if hematuria or obvious rectal bleeding, such as from hemorrhoids, is present or from premenopausal women during or in the first three days after a menstrual cycle.

Method Name

Guaiac

CPT Code Information

82270

LOINC Code Information

2335-8

Restrictions

For 2 days prior to testing abstain from meat and peroxidase rich raw fruits and vegetables (turnips, melons, radishes and horseradish). Avoid alcohol, aspirin, Vitamin C and other gastric irritants prior to testing.