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Test Code HBELC Hemoglobin Electrophoresis Cascade, Blood

Reporting Name

HGB Electrophoresis Cascade

Useful For

Diagnosis of thalassemias and hemoglobin variants

 

Evaluation of unexplained microcytosis

Profile Information

Test ID Reporting Name Available Separately Always Performed
A2F Hemoglobin A2 and F No Yes
HBEL Hemoglobin Electrophoresis, B No Yes

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
HPFH Hemoglobin F, Red Cell Distrib, B Yes No
SDEX Hemoglobin S, Scrn, B Yes No
IEF IEF Confirms No No
MASS Hb Variant by Mass Spec, B No No
HGBMO HGB Electrophoresis, Molecular No No
UNHB Unstable Hemoglobin, B No No

Testing Algorithm

Hemoglobin electrophoresis cascade will always include hemoglobin A(2) and F and hemoglobin electrophoresis.

 

Reflex testing-Hemoglobin electrophoresis reflex testing, performed at additional charge, may include any or all of the following as indicated to identify rare hemoglobin variants present: hemoglobin S screen, unstable hemoglobin, isoelectric focusing confirms, hemoglobin variant by mass spectrometry, hemoglobin F red cell distribution, beta-globin gene, large deletion/duplication, alpha-globin gene sequencing, and beta-globin gene sequencing.

Performing Laboratory

Mayo Medical Laboratories in Rochester

Specimen Type

Whole Blood EDTA


Specimen Required


Container/Tube:

Preferred: Lavender top (EDTA)

Acceptable: ACD (solution B), green top (sodium heparin)

Specimen Volume: 10 mL

Collection Instructions: Do not transfer blood to other containers.

Additional Information:

1. Patient's age is required.

2. Include recent transfusion information.

3. For information on thalassemias and appropriate test ordering, see Thalassemia Tests in Special Instructions.


Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time
Whole Blood EDTA Refrigerated 7 days

Reference Values

HEMOGLOBIN A

1-30 days: 5.9-77.2%

1-2 months: 7.9-92.4%

3-5 months: 54.7-97.1%

6-8 months: 80.0-98.0%

9-12 months: 86.2-98.0%

13-17 months: 88.8-98.0%

18-23 months: 90.4-98.0%

≥24 months: 95.8-98.0%

 

HEMOGLOBIN A2

1-30 days: 0.0-2.1%

1-2 months: 0.0-2.6%

3-5 months: 1.3-3.1%

≥6 months: 2.0-3.3%

 

HEMOGLOBIN F

1-30 days: 22.8-92.0%

1-2 months: 7.6-89.8%

3-5 months: 1.6-42.2%

6-8 months: 0.0-16.7%

9-12 months: 0.0-10.5%

13-17 months: 0.0-7.9%

18-23 months: 0.0-6.3%

≥24 months: 0.0-0.9%

 

VARIANT

No abnormal variants

 

VARIANT 2

No abnormal variants

 

VARIANT 3

No abnormal variants

Day(s) and Time(s) Performed

Monday through Saturday 

Test Classification

This test was developed and its performance characteristics determined by Laboratory Medicine and Pathology, Mayo Clinic. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

Hemoglobin Electrophoresis Cascade

83020-Quantitation by electrophoresis

83021-Quantitation by HPLC

 

IEF Confirms

82664-Electrophoresis, not elsewhere specified (if appropriate)

 

Hemoglobin, Unstable, Blood

83068 (if appropriate)

 

Hemoglobin Variant by Mass Spectrometry (MS), Blood

83789 (if appropriate)

 

Hemoglobin Electrophoresis, Molecular

81405-HBA1/HBA2 full sequence
81404-HBB (hemoglobin, beta) full sequence
81403-HBB (hemoglobin, beta, beta-globin) (eg, beta thalassemia), duplication/deletion analysis (if appropriate)
 

Hemoglobin S, Screen, Blood

85660 (if appropriate)

 

Hemoglobin F, Red Blood Cell Distribution, Blood

88184 (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
HBELC HGB Electrophoresis Cascade In Process

 

Result ID Test Result Name Result LOINC Value
2380 Hemoglobin A 20572-4
2381 Hemoglobin A2 4551-8
2382 Hemoglobin F 4576-5
2383 Variant 32017-6
29224 Variant 2 32017-6
29225 Variant 3 32017-6
2101 Interpretation 49316-3

Clinical Information

A large number (>800) of variants of hemoglobin (Hb) have been recognized. They are identified by capital letters (eg, Hb A or Hb S), or by the city in which the variant was first discovered (eg, Hb Koln).

 

Mayo Medical Laboratories receives specimens for this test from a wide geographic area and nearly one-half of all specimens received exhibit abnormalities. The most common abnormality is an increase in Hb A2 to about 4% to 8%, which is diagnostic of beta-thalassemia minor. A wide variety of other hemoglobinopathies also have been encountered. Ranked in order of relative frequency, these are: Hb S (sickle cell disease and trait), C, E, Lepore, G-Philadelphia, H, D-Los Angeles, Koln, Constant Spring, O-Arab, and others. Hb C and S are found mostly in people from west or central Africa and Hb E and H in people from Southeast Asia. Hemoglobin electrophoresis is often used in the evaluation of unexplained microcytosis, thus accounting for the frequent detection of Hb Lepore, which is relatively common in Italians and others of Mediterranean ancestry and in Hb E, which is relatively common in Southeast Asians resettled in the United States; microcytosis is characteristic of both Hb Lepore and Hb E.

 

Alpha-thalassemia is very common in the United States, occurring in approximately 30% of African Americans and accounting for the frequent occurrence of microcytosis in persons of this ethnic group. Some alpha-thalassemias (ie, hemoglobin variants H, Barts, and Constant Spring) are usually easily identified in the hemoglobin electrophoresis protocol. However, alpha-thalassemias that are from only 1 or 2 alpha-globin gene deletions are not recognized. Unfortunately, there is no easy test for the diagnosis of these alpha-thalassemias (see ATHAL / Alpha-Globin Gene Analysis).

 

Alpha-thalassemia trait itself is a harmless condition.

Interpretation

The types of hemoglobin present are identified, quantitated, and an interpretive report is issued.

Clinical Reference

Hoyer JD, Hoffman DR: The Thalassemia and hemoglobinopathy syndromes. In Clinical Laboratory Medicine. Second edition. Edited by KD McMlatchey. Philadelphia, Lippincott Williams and Wilkins, 2002, pp 866-895

Analytic Time

1 day/2 to 25 days if structural and/or molecular studies are required.

Reject Due To

Hemolysis

No (lab will evaluate)

Lipemia

NA

Icterus

NA

Other

NA

Method Name

A2F: Cation Exchange/High-Performance Liquid Chromatography (HPLC)

HBEL: Capillary Electrophoresis

IEF: Isoelectric Focusing

MASS: Mass Spectrometry (MS)

HGBMO: Polymerase Chain Reaction (PCR) Analysis/Multiplex Ligation-Dependent Probe Amplification (MLPA), Polymerase Chain Reaction (PCR)/DNA Sequencing

(PCR is utilized pursuant to a license agreement with Roche Molecular Systems, Inc.)

Forms

1. New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (Supply T576) is available in Special Instructions.

2. Thalassemia/Hemoglobinopathy Patient Information (T358) in Special Instructions

3. If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

General Request Form (T239) (http://www.mayomedicallaboratories.com/it-mmfiles/general-request-form.pdf)

Benign Hematology Test Request Form (T755) (http://www.mayomedicallaboratories.com/it-mmfiles/benign-hematology-test-request-form.pdf)