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Occult Blood, Gastric (Gastroccult™)

Test Codes

EPIC: LAB5256, OCBFL

Specimen Collection Criteria

Collect: Gastric aspirate obtained by nasogastric intubation or vomitus in a sterile collection container.

• No special patient preparation is required.
• Send specimen to the Laboratory immediately after collection.

Physician Office/Draw Specimen Preparation

Maintain specimen at room temperature (20-26°C or 68-78.8°F) prior to transport.

Preparation for Courier Transport

Transport: Gastric specimen, at room temperature (20-26°C or 68-78.8°F).

Rejection Criteria

Specimens not collected and processed as indicated.

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 24 hours
Refrigerated (2-8°C or 36-46°F): 24 hours
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days

Laboratory

Grosse Pointe Microbiology Laboratory
Royal Oak Automated Chemistry Laboratory
Troy Chemistry Laboratory
Dearborn Microbiology Laboratory

Performed

Sunday – Saturday, 24 hours a day.
STAT results available within 1 hour of receipt in the Laboratory.
Routine results available within 24 hours of receipt in the Laboratory.

Reference Range

Negative.

Test Methodology

Colorimetric.

Interpretation

Gastroccult is a screening test for presence of occult blood in a gastric aspirate. Many foods (e.g. incompletely cooked meat, raw fruits and vegetables) have peroxidase activity which may produce a false positive Gastroccult test result. Thus, a positive result does not always indicate the presence of human blood.

Ascorbic Acid (Vitamin C) has been shown to cause false-negative test results for occult blood in feces. This can be expected to be true for the Gastroccult test also.

As with any occult blood test, the results of the Gastroccult test cannot be considered conclusive evidence of the presence or absence of upper gastrointestinal bleeding or pathology. Gastroccult tests are designed for preliminary screening as an aid to diagnosis. They are not intended to replace other diagnostic procedures such as gastroscopic examination or radiographic studies. Gastroccult test results should be used only in conjunction with other information relevant to the clinical status of the patient. A positive test result may suggest the need for more careful monitoring of the patient.

Clinical Utility

This assay provides a rapid screening method for detecting the presence of occult blood in gastric aspirates or vomitus. Gastroccult slides are used to aid in the diagnosis and management of various gastric conditions. The identification of occult blood can be useful in the early detection of gastric trauma or deteriorating gastric conditions, and in evaluating antacid therapy.

Contacts

Last Updated

4/26/2022