Laboratory Lab results are too important to go anywhere else.

GUAIAC Screening (Southeast Michigan, West ED and Rural Health Clinic Use Only)

Fecal Occult Blood Test, FOBT

Test Codes

EPIC: LAB695, Single Specimen Screening/Unspecified: EPIC: LAB5093, Beaker: OBSS, Single Specimen Diagnostic: EPIC: LAB5092, Beaker: OBDS

Department

Chemistry

Instructions

In the outpatient setting, it is recommended that Occult Blood, Fecal Immunological Test (OBFIT) for colorectal cancer screening be performed.

Patient Instructions & Special Diagnostic Diet Prior to Occult Blood Testing:

• Do not collect samples during, or until three days after your menstrual period, or while you have bleeding hemorrhoids or blood in your urine.
• Do not consume the following drugs, vitamins and foods:
  • Avoid aspirin or other non-steroidal anti-inflammatory drugs for 7 days prior to and during the test period.
  • Avoid Vitamin C in excess of 250 mg per day (from all sources, dietary and supplemental)* for 72 hours prior to and during the test period.
  • Red meat (beef, lamb), including processed meats and liver, raw fruits and vegetables (especially melons, radishes, turnips and horseradish) should not be eaten for 3 days prior to and during the test period.
• Eat a well-balanced diet including fiber such as bran cereals, fruits, and vegetables (other than those indicated above) for at least 48 hours prior to and throughout the testing period.
• The suggested diet can provide roughage to help uncover "silent" lesions. Bleeding from gastrointestinal lesions may be intermittent.
• Protect test card(s) from heat, light and volatile chemicals (e.g., iodine or bleach).
• Keep cover flap of test card(s) closed when not in use.

* Caution: some iron supplements contain quantities of Vitamin C which exceed 250 mg per day.

Specimen Collection Criteria

Collect: Fresh, random, stool specimen, from a bowel movement. Place specimen in a sterile, screw-capped container (all campuses), 

OR (for Grosse Pointe, Royal Oak or Troy)

• Apply thin smear of specimen to test card(s).
• A single test card may be obtained for STAT Inpatient testing at Grosse Pointe, Royal Oak and Troy hospital campuses:
  • Grosse Pointe: Contact the Microbiology Laboratory (ext. 1802) to obtain test card. The test card with thin smear of specimen must be returned to the Microbiology Laboratory (Main Laboratory P-Tube Station).
  • Royal Oak: Contact the STAT Laboratory (ext. 80526) to obtain test card. The test card with thin smear of specimen must be returned to the STAT Laboratory (3 Central or P-Tube Station #311).
  • Troy: Contact Specimen Reception (ext. 48030) to obtain test card. The test card with thin smear of specimen must be returned to the Laboratory (P-Tube Station #201).
• Please see the table below for test ordering and specimen information.

Test Name*	Specimen	EPIC Code	Beaker Code
Occult Blood Stool, Screen	Sterile Cup or STAT Inpatient Prepared test card	LAB5093	OBSS
Occult Blood Stool, Diagnostic (RO, Troy or GP ONLY)	Sterile Cup or STAT Inpatient Prepared test card	LAB5092	OBSD

*Default order is for Screen when not specified.

Physician Office/Draw Specimen Preparation

Maintain stool specimens or specimen test card at room temperature (20-26°C or 68-78.8°F).

Preparation for Courier Transport

Transport: Stool specimens or specimen test card, at room temperature (20-26°C or 68-78.8°F).

Rejection Criteria

• Test card(s) greater than 14 days old.
• Specimens not collected and processed as indicated.

In-Lab Processing

Specimens may be received as a stool specimen in a sterile collection container or as a prepared test card(s).

Storage

Specimen Stability for Testing:

Test Card(s)
Room Temperature (20-26°C or 68-78.8°F): 14 days
Refrigerated (2-8°C or 36-46°F): 14 days
Frozen (-20°C/-4°F or below): Unacceptable

Unpreserved Stool
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:

Test card(s) are disposed immediately after testing at Troy and Grosse Pointe (48 hours at Royal Oak).

Unpreserved stool specimens are refrigerated (2-8°C or 36-46°F) for 48 hours (Royal Oak), or 7 days (Troy, Grosse Pointe and Farmington Hills).

Laboratory

Canton Chemistry Laboratory
Farmington Hills Chemistry Laboratory 
Grosse Pointe Chemistry Laboratory 
Lenox Main Laboratory
Livonia Main Laboratory
Royal Oak Automated Chemistry Laboratory 
Taylor Chemistry Laboratory
Troy Chemistry Laboratory
Wayne Chemistry Laboratory 

Performed

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

Reference Range

Negative.

Test Methodology

Colorimetric.

Royal Oak/Troy/Grosse Pointe/Farmington Hills – Beckman Coulter Hemoccult® SENSA® Slides (test cards).

Interpretation

• Positive results may be seen in GI malignancies, gastritis, variceal bleeding, diverticular disease, peptic ulcers, GI polyps, ischemic bowel disease, ulcerative colitis, Crohn's disease, shigellosis, amebiasis, trauma, bleeding diatheses, vasculitis, Turner's syndrome, uremia, intussusception, neurofibromatosis and Kaposi's sarcoma.
• False positive results may be caused by eating red meat during the three days prior to specimen collection, eating raw fruits and vegetables high in peroxidase (horseradish, turnips, melons, radishes) when fecal samples are tested immediately after collection, and by substances which can irritate the gastrointestinal tract and cause bleeding (aspirin, etc.).
• False negative results may be caused by ascorbic acid (Vitamin C) intake of more than 250 mg/day and by excessive amounts of Vitamin C enriched foods.

Clinical Utility

This assay is used to detect intestinal bleeding.

CPT Codes

82270

Contacts

Last Updated

11/8/2024