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Test Code LABS0454 Hemoglobin F, Red Cell Distribution, Blood

Additional Codes

Mayo Test Code: HPFH

Useful For

Distinguishing large deletional hereditary persistence of fetal hemoglobin from other conditions with increased percentage of fetal hemoglobin


Determining the distribution of Hb F within red blood cells

Performing Laboratory

Mayo Medical Laboratories in Rochester

Specimen Type

Whole Blood EDTA

Advisory Information

This test is a flow cytometry assay that determines the distribution of hemoglobin F (Hb F) within red blood cells. The HGBCE / Hemoglobin Variant, A2 and F Quantitation, Blood test is intended for monitoring purposes, such as the increase in Hb F after therapy, or the levels of hemoglobin variants after transfusion.


This test should not be ordered for fetal-maternal bleed. If fetal maternal bleed assessment is desired, see FMB / Fetomaternal Bleed, Flow Cytometry, Blood.

Necessary Information

1. Indicate the percent of hemoglobin F detected by hemoglobin electrophoresis. If this is not indicated, we will perform HBF / Hemoglobin F, Blood.

2. Indicate the reason for testing.

Specimen Required

Container/Tube: Lavender top (EDTA)
Specimen Volume:
3 mL

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time
Whole Blood EDTA Refrigerated 7 days

Reference Values

Reported as heterocellular or homocellular

Day(s) and Time(s) Performed

Monday through Saturday; continuously

Test Classification

This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information


Reject Due To


Mild reject; Gross reject


Mild OK; Gross OK





Testing Algorithm

The percent of the patient's hemoglobin F is very important to the clinical utility of this test. HBF / Hemoglobin F, Blood will be performed at an additional charge to determine if Hemoglobin F, Red Cell Distribution testing is warranted. If the hemoglobin F value is normal for age or if the value is less than 5%, the red cell distribution test will not be performed. Samples with hemoglobin F (Hb F) levels above 35% will be accepted but are discouraged due to decreased test specificity. For these markedly elevated Hb F levels, a hemoglobin electrophoresis profile with request for beta globin gene molecular testing for elevated Hb F levels is recommended.


For information on thalassemias and appropriate test ordering, see Thalassemia/Hemoglobinopathy Patient Information in Special Instructions.

Method Name

Flow Cytometry

Additional Tests

Test ID Reporting Name Available Separately Always Performed
HBF Hemoglobin F, B No Yes


If not ordering electronically, complete, print, and send a Benign Hematology Test Request Form (T755) with the specimen (