ARUP's Laboratory Test Directory

0050613: Hemoglobin (Hb) A2 & F by Column

Test Mnemonic: HGBA2F COL
Methodology: High Performance Liquid Chromatography

Performed: Sun-Sat

Reported: 1-4 days

Specimen Required:  
Collect: One 5 mL lavender (EDTA) or pink (K2EDTA). 

Transport: 5 mL whole blood at 2-8°C. (Min: 1 mL)

Pediatric Collection/Transport: 0.2 mL whole blood (lavender, EDTA) at 2-8°C.

Unacceptable Conditions: Ambient and frozen samples.

Stability: Ambient: Unacceptable; Refrigerated: 1 week; Frozen: Unacceptable

Reference Interval:
Components            Reference Interval
Hb A2              Age dependent - By Report
Hb F                        Age dependent - By Report

Interpretive Data:
In laboratory confirmation of a b-thalassemia trait diagnosis, Hb A2 levels should be considered in conjunction with family history plus laboratory data, including serum iron and iron binding capacity, red cell morphology, hemoglobin, hematocrit, and mean corpuscular volume (MCV).

Please note that patients with the combination of iron deficiency and b-thalassemia may have a normal A2 level. An elevated A2 level cannot be used to screen for b-thalassemia in these cases.

 
Patient State Hb A2 Level Hb F Level
Heterozygous b-thalassemia 4-9% 1-5%
Homozygous b-thalassemia Normal or Increased 80-100%
Heterozygous HPFH Less than 1.5% 10-20%
Homozygous HPFH Absent 100%


Note:
Recommend quantitation of hemoglobin for definitive diagnosis after 1 year of age.

CPT Code(s):
83021

 

 

 
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