Laboratory Test Guide

Hemoglobin A1C (by HPLC)

General Information

Lab Name

Hemoglobin A1C by HPLC

Lab Code

A1C

Epic Name

Hemoglobin A1C, HPLC

Description

A1c HPLC test utilizes principles of ion-exchange high-performance liquid chromatography (HPLC). HbA1c testing can be used to diagnose diabetes, with a value of ≥6.5% (≥48 mmol/mol), and prediabetes, with an HbA1c level of 5.7–6.4% (39–47 mmol/mol). HbA1c should be measured routinely in most individuals with diabetes mellitus to document their degree of glycemic control, with the goal HbA1c <7.0%. Detection and treatment of pre-diabetes may reduce or eliminate the risk of developing Type 2 diabetes and related complications.

Synonyms

Glycated Hemoglobin, Glycohemoglobin, Glycosylated Hemoglobin, HBA1C by HPLC, HGBA1C

Interpretation

Method

High Performance Liquid Chromatography (HPLC)

Reference Range

Units: %

Female		Male
Age	Range	Age	Range
0-	4.0-5.6	0-	4.0-5.6

Effective date: 10/01/2024

Ref. Range Notes

Prediabetes: 5.7 - 6.4%
Diabetes: >6.4%
Glycemic control for adults with diabetes: <7.0%

Interferences and Limitations

The HbA1c test should not be used to diagnose diabetes in patients with the following conditions:

Recent blood loss
Recent transfusion
Significant iron deficiency
Hemolytic anemia or other hemolytic disease
Hemoglobinopathies and thalassemias
Malignancies or severe chronic hepatic and renal disease

Hemoglobin F concentration up to 30% does not interfere with the test.

Ordering & Collection

Specimen Type

Blood

Collection

3 mL LAVENDER HEMOGARD tube

Unacceptable: Non-human specimen

Handling Instructions

Instructions for Outside Clients:

This test is for ALL routine HbA1c's from blood tubes sent to the lab. (Preliminary results before clinic visit are available only at Roosevelt and South Lake Union laboratories. See rapid Point of Care test A1CRPD.) Non-human specimens cannot be assayed as the method cannot identify non-human hemoglobins.

Stability: Room Temperature 4 days; Refrigerated 6 days

Quantity

requested: 3 mL whole blood
minimum: 1 mL whole blood

Processing

Refrigerate whole blood in Red Cell Disorders (RCD) rack upon receipt or addon.

Unacceptable: Other anticoagulants, Frozen specimens

Stability: Room Temperature 4 days; Refrigerated 6 days

Processing Staff: RCD techs may reflex to the alternate method A1CRPD in cases with interference by hemoglobin variants.

Performance

LIS Dept Code

Red Cell Disorders (RCD)

Performing Location(s)

HMC	Red Cell Disorders 206-520-4600 325 9th Ave, Rm # GWH-47, Seattle, WA 98104-2420

Frequency

Frequency: Monday-Friday, except holidays. Samples sent to lab are generally run next working day.