CPT® Code 81259

Official Description

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

Common Language Description

Molecular genetic testing is a critical procedure used to identify specific mutations in the HBA1 and HBA2 genes, which are responsible for encoding the alpha globin chains of hemoglobin. These genes are located on chromosome 16 within the alpha globin locus and play a significant role in various hemoglobin disorders. Among these disorders, alpha thalassemia is the most prevalent globally, resulting from the absence or reduced production of alpha globin chains due to deletions in the alpha A genes, which include both HBA1 and HBA2. There are several known variants of alpha thalassemia, including SEA, THAI, FIL, MED, and alpha20.5, which involve deletions of both HBA1 and HBA2 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 by 31 amino acids. The inheritance pattern of these disorders is autosomal recessive, meaning that individuals must inherit mutations in both copies of the gene from their parents to develop 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 loss of all four alpha globin genes, resulting in severe complications such as fetal and perinatal death, edema, and severe anemia. Another form, Hemoglobin H (HbH) disease, occurs with the loss of three alpha genes and presents with moderate anemia and splenomegaly. Carrier states may exhibit mild anemia and can often be misdiagnosed as iron deficiency anemia. Silent carriers, who lose only one alpha gene, are typically asymptomatic or may show very mild symptoms. 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 conditions.

1. Indications

The molecular genetic testing for HBA1 and HBA2 gene analysis is indicated in the following scenarios:

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 genetic factors are involved.
Family History of Hemoglobin Disorders Individuals with a known family history of hemoglobin disorders may be tested to assess their risk of carrying mutations in the HBA1 or HBA2 genes.

2. Procedure

The procedure for HBA1 and HBA2 gene analysis involves several key steps to ensure accurate identification of mutations:

Sample Collection A biological sample, typically blood or saliva, is collected from the patient. This sample contains the DNA necessary for genetic analysis.
DNA Extraction The DNA is extracted from the collected sample using standardized laboratory techniques to isolate the genetic material for analysis.
Full Gene Sequencing The extracted DNA undergoes full gene sequencing, which involves analyzing the entire coding region of the HBA1 and HBA2 genes to identify any mutations or variants present.
Data Analysis The sequencing data is then analyzed using bioinformatics tools to compare the patient's genetic information against known sequences, identifying any deviations that may indicate mutations associated with hemoglobin disorders.
Reporting Results The results of the genetic analysis are compiled into a report, detailing any identified mutations and their potential implications for the patient's health and family.

3. Post-Procedure

After the completion of the HBA1 and HBA2 gene analysis, patients may receive counseling regarding the results. If mutations are identified, healthcare providers will discuss the implications for the patient's health, potential treatment options, and the risk of passing the mutations to offspring. Follow-up testing may be recommended for family members, especially if a hereditary condition is confirmed. Additionally, patients may be advised on monitoring for symptoms associated with hemoglobin disorders and the importance of regular medical check-ups to manage any related health issues.

Short Descr	HBA1/HBA2 FULL GENE SEQUENCE
Medium Descr	HBA1/HBA2 GENE ANALYSIS FULL GENE SEQUENCE
Long Descr	HBA1/HBA2 (alpha globin 1 and alpha globin 2) (eg, alpha thalassemia, Hb Bart hydrops fetalis syndrome, HbH disease), gene analysis; full gene sequence
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

90	Reference (outside) laboratory: when laboratory procedures are performed by a party other than the treating or reporting physician or other qualified health care professional, the procedure may be identified by adding modifier 90 to the usual procedure number.
XU	Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service