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Test Code HQ HemoQuant, Feces

Reporting Name

Hemoquant, F

Useful For

Detection of blood in feces

 

Evaluation of iron deficiency

 

Detection of bleeding as a complication of anticoagulant therapy and other medication regimens

 

This test is not specific for bowel cancer.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Fecal


Specimen Required


Patient Preparation: Patient should refrain from ingesting red meat and aspirin-containing products (eg, Excedrin, Aspirin) for 3 days prior to specimen collection.

Collection Container/Tube: Hemoquant Specimen Collection (T134)

Submission Container/Tube: Screw-capped tube

Specimen Volume: 1 g

Collection Instructions: Collect random specimen from a single defecation.


Specimen Minimum Volume

1 g

Specimen Stability Information

Specimen Type Temperature Time Special Container
Fecal Refrigerated (preferred) 7 days
  Ambient  7 days
  Frozen 

Reference Values

Normal:

≤2.0 mg total hemoglobin/g feces

 

Marginal:

2.1-4.0 mg total hemoglobin/g feces*

*2.1-4.0 mg Hb/g is considered marginally elevated, but not clinically significant, if red meat, warfarin, or aspirin was ingested 72 hours prior to collection.

 

Elevated:

>4.0 mg total hemoglobin/g feces

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

84126

LOINC Code Information

Test ID Test Order Name Order LOINC Value
HQ Hemoquant, F 27396-1

 

Result ID Test Result Name Result LOINC Value
2410 Fecal Hemoglobin 27396-1

Clinical Information

Several noninvasive tests are available to detect gastrointestinal (GI) bleeding. However, guaiac type and immunochemical tests for occult bleeding are affected by the presence of reducing or oxidizing substances and are insensitive for the detection of upper GI tract (esophagogastric) bleeding, where most clinically significant occult GI bleeding occurs.

 

The HemoQuant test is the most reliable, noninvasive test currently available for detecting bleeding of the esophago-GI tract. Unlike other tests for blood in feces, this test detects both intact heme and porphyrins from partly degraded heme. Additionally, test results are not complicated by either the water content of the specimen or the presence of reducing or oxidizing substances. Furthermore, HemoQuant testing is sensitive to both proximal and distal sources of occult GI bleeding.

 

Normally, one gram of feces may contain 0.0 to 2.0 mg hemoglobin; this corresponds to a daily loss of up to 2 mL blood. A demonstration of increased Hb in feces indicates bleeding in the alimentary tract (or ingestion of anticoagulants, aspirin, or red meat).

Interpretation

Elevated levels are an indicator of the presence of blood in the feces, either from benign or malignant causes.

Cautions

Heme from ingested red meat will increase HemoQuant test values. Patients should be advised to avoid eating red meat for 3 days before collecting specimens. Fish and poultry may be substituted.

 

The elevated porphyrins of lead intoxication, erythrocytic protoporphyria and variegate porphyria may raise HemoQuant values in the absence of gut bleeding.

 

Recent studies have indicated that cancerous lesions in their early stages often do not bleed or bleed only intermittently.

Clinical Reference

1. Ahlquist DA, McGill DB, Schwartz S, Taylor WF, Ellefson M, Owen RA. HemoQuant, a new quantitative assay for fecal hemoglobin. Comparison with Hemoccult. Ann Intern Med. 1984;101(3):297-302

2. Ahlquist DA, Wieand HS, Moertel CG, et al. Accuracy of fecal occult blood screening for colorectal neoplasia. A prospective study using Hemoccult and HemoQuant tests. JAMA. 1993;269(10):1262-1267

3. Harewood GC, McConnell JP, Harrington JJ, Mahoney DW, Ahlquist DA. Detection of occult upper gastrointestinal bleeding: performance differences in fecal blood tests. Mayo Clin Proc. 2002;77(1):23-28

4. Ahlquist DA, McGill DB, Schwartz S, Taylor WF, Owens RA. Fecal blood levels in health and disease. A study using HemoQuant. N Engl J Med. 1985;312(22):1422-1428

5. Barber MD, Abraham A, Brydon WG, Waldron BM, Williams AJ. Assessment of faecal occult blood loss by qualitative and quantitative methods. J R Coll Surg Edinb. 2002;47(2):491-494

6. Rockey DC, Altayar O, Falck-Ytter Y, Kalmaz D. AGA Technical review on gastrointestinal evaluation of iron deficiency anemia. Gastroenterology. 2020;159(3):1097-1119. doi:10.1053/j.gastro.2020.06.045

Method Description

Hemoglobin and the heme released by hemoglobin degradation are converted to porphyrins. These porphyrins are quantified by fluorescence measurement after extraction of any interfering fluorescing substances.(Schwartz S, Dahl J, Ellefson M, Ahlquist D. The "HemoQuant" test: a specific and quantitative determination of heme [hemoglobin] in feces and other materials. Clin Chem 1983;29[12]:2061-2067)

Specimen Retention Time

14 days

Reject Due To

Gross hemolysis OK

Method Name

Fluorescence Quantitation

Secondary ID

607706

Day(s) Performed

Monday through Saturday

Report Available

1 to 2 days