CPT® Code 81258

Official Description

HBA1/HBA2 (alpha globin 1 and alpha globin 2) (eg, alpha thalassemia, Hb Bart hydrops fetalis syndrome, HbH disease), gene analysis; known familial variant

Common Language Description

Molecular genetic testing is a critical procedure used to identify specific mutations in the HBA1 or HBA2 genes, which are responsible for encoding the alpha globin protein. These genes are located on chromosome 16 within the alpha globin locus and are integral to the production of hemoglobin, the protein in red blood cells that carries oxygen throughout the body. Various hemoglobin disorders are associated with mutations in these genes, with alpha thalassemia being the most prevalent worldwide. This condition arises from the absence or reduced production of alpha globin chains, often due to deletions affecting the HBA1 and HBA2 genes. There are several known variants of alpha thalassemia, including SEA, THAI, FIL, MED, and alpha20.5, which involve deletions of both genes from the same chromosome. Other variants, such as alpha3.7 and alpha4.2, result in the deletion of a single alpha gene, while the Constant Spring (HbCS) variant is characterized by a mutation in the termination codons of HBA2, leading to an elongated protein structure. The inheritance pattern of these disorders is autosomal recessive, meaning that individuals must inherit mutations from both parents to develop significant hemoglobin disorders. Those who inherit a mutation from only one parent become carriers of the disease. Clinically significant forms of alpha thalassemia include Hb Bart, which can lead to hydrops fetalis syndrome due to the complete loss of all four alpha globin genes, and Hemoglobin H (HbH) disease, which results from the loss of three alpha genes. Symptoms of these conditions can range from severe anemia and fetal complications to mild anemia in carrier states. Molecular genetic testing is particularly indicated for individuals exhibiting symptoms of hemoglobin disorders, women with a history of fetal loss associated with hydrops fetalis syndrome, or those with a family history of these genetic conditions.

1. Indications

The molecular genetic testing for HBA1 and HBA2 gene analysis is indicated for several specific conditions and scenarios, including:

Symptoms of Hemoglobin Disorders Individuals presenting with clinical symptoms associated with hemoglobin disorders may require testing to identify specific mutations in the HBA1 or HBA2 genes.
Fetal Loss with Evidence of Hydrops Fetalis Syndrome Women who have experienced fetal loss accompanied by signs of hydrops fetalis syndrome should undergo testing to determine if a genetic mutation is present.
Family History of Hemoglobin Disorders Individuals with a known family history of hemoglobin disorders may be tested to assess their risk of carrying or developing these conditions.

2. Procedure

The procedure for HBA1 and HBA2 gene analysis involves several key steps, which are detailed as follows:

Sample Collection A biological sample, typically blood or saliva, is collected from the patient. This sample serves as the source of DNA for the genetic analysis.
DNA Extraction The DNA is extracted from the collected sample using standardized laboratory techniques to ensure the integrity and purity of the genetic material for testing.
Mutation Analysis The extracted DNA is then analyzed for known familial variants in the HBA1 and HBA2 genes. This analysis may involve techniques such as polymerase chain reaction (PCR) and sequencing to identify specific mutations.
Result Interpretation Once the analysis is complete, the results are interpreted by a qualified geneticist or laboratory professional. They will determine if any mutations associated with hemoglobin disorders are present.
Reporting The findings are compiled into a report that details the presence or absence of known familial variants in the HBA1 and HBA2 genes. This report is then provided to the referring physician for further clinical decision-making.

3. Post-Procedure

After the gene analysis procedure, patients may receive counseling regarding the results, especially if a mutation is identified. This counseling can include discussions about the implications of the findings for the patient and their family members, potential health risks, and options for further testing or management. Follow-up appointments may be necessary to address any questions or concerns and to discuss potential next steps based on the results of the genetic testing.

Short Descr	HBA1/HBA2 GENE FAM VRNT
Medium Descr	HBA1/HBA2 GENE ANALYSIS KNOWN FAMILIAL VARIANT
Long Descr	HBA1/HBA2 (alpha globin 1 and alpha globin 2) (eg, alpha thalassemia, Hb Bart hydrops fetalis syndrome, HbH disease), gene analysis; known familial variant
Status Code	Statutory Exclusion (from MPFS, may be paid under other methodologies)
Global Days	XXX - Global Concept Does Not Apply
PC/TC Indicator (26, TC)	9 - Not Applicable
Multiple Procedures (51)	9 - Concept does not apply.
Bilateral Surgery (50)	9 - Concept does not apply.
Physician Supervisions	09 - Concept does not apply.
Assistant Surgeon (80, 82)	9 - Concept does not apply.
Co-Surgeons (62)	9 - Concept does not apply.
Team Surgery (66)	9 - Concept does not apply.
Diagnostic Imaging Family	99 - Concept Does Not Apply
CLIA Waived (QW)	No
APC Status Indicator	Service Paid under Fee Schedule or Payment System other than OPPS
Type of Service (TOS)	5 - Diagnostic Laboratory
Berenson-Eggers TOS (BETOS)	none
MUE	1