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The CPT® Code 81106 pertains to the gene analysis for Human Platelet Antigen 2 (HPA-2) genotyping, specifically focusing on the GP1BA gene, which encodes the glycoprotein Ib alpha polypeptide. This analysis is particularly relevant in the context of neonatal alloimmune thrombocytopenia (NAIT) and post-transfusion purpura, both of which are conditions associated with platelet alloantigens. The HPA-2a/b allele variants are identified through this testing, which is crucial for understanding the genetic factors that contribute to these conditions. Platelet alloantigens arise from single nucleotide polymorphisms (SNPs) in the genes responsible for coding platelet membrane glycoproteins, leading to variations that can affect platelet function and immune response. The gene analysis may be utilized in various clinical scenarios, including the identification of HPA-2 variants in symptomatic neonates, screening for fetal alloimmunization during pregnancy, and assessing the risk for NAIT in future pregnancies or post-transfusion purpura. NAIT is a serious condition that occurs when maternal IgG antibodies cross the placenta and target paternally derived alloantigens present on fetal platelets, potentially leading to severe complications such as thrombocytopenia and intracranial hemorrhage. On the other hand, post-transfusion purpura is characterized by significant bleeding that occurs 5 to 10 days after a platelet transfusion containing incompatible HPA or platelet-specific antigens. The testing process involves obtaining samples from blood, amniotic fluid, or cultured amniocytes, which are then analyzed using multiplex polymerase chain reaction (PCR) techniques to detect the presence of specific allele variants through fluorescence observation.
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Neonatal Alloimmune Thrombocytopenia (NAIT) - This condition occurs when maternal IgG antibodies cross the placenta and attack paternally derived alloantigens on fetal platelets, leading to severe thrombocytopenia and potential complications such as intracranial hemorrhage.
Post-Transfusion Purpura - This condition arises when a woman receives a platelet transfusion containing incompatible HPA or platelet-specific antigens, resulting in severe bleeding 5 to 10 days following the transfusion.
Fetal Alloimmunization Screening - The gene analysis may be performed to screen for fetal alloimmunization during pregnancy, which is critical for managing potential risks to the fetus.
Maternal Risk Assessment - The test can also be used to assess the maternal risk for NAIT in future pregnancies, providing valuable information for prenatal care and planning.
Step 1: Sample Collection - Blood, amniotic fluid, or cultured amniocytes are collected as the primary samples for analysis. Each sample type is obtained through a separate reportable procedure, ensuring that the correct specimen is used for the gene analysis.
Step 2: Testing Methodology - The collected samples undergo testing using multiplex polymerase chain reaction (PCR) techniques. This method allows for the amplification of specific DNA sequences associated with the HPA-2 gene variants.
Step 3: Allele-Specific Primer Extensions - During the PCR process, allele-specific primer extensions are utilized to target the common variant HPA-2a/b (T145M). This step is crucial for accurately identifying the presence of the specific allele variants in the samples.
Step 4: Fluorescence Observation - The final step involves fluorescence observation, which enables the detection of the amplified DNA and confirms the presence of the HPA-2 variants. This observation is essential for interpreting the results of the gene analysis.
After the gene analysis is completed, the results are typically reviewed and interpreted by a qualified healthcare professional. The findings can provide critical information regarding the presence of HPA-2 variants, which may influence clinical management decisions for the patient, particularly in the context of NAIT and post-transfusion purpura. Follow-up care may include counseling for the patient regarding the implications of the test results, especially in relation to future pregnancies or transfusion needs. It is important to monitor for any symptoms associated with NAIT or post-transfusion purpura, and appropriate interventions should be planned based on the results of the gene analysis.
| Short Descr | HPA-2 GENOTYPING | Medium Descr | HPA-2 GENOTYPING GENE ANALYSIS COMMON VARIANT | Long Descr | Human Platelet Antigen 2 genotyping (HPA-2), GP1BA (glycoprotein Ib [platelet], alpha polypeptide [GPIba]) (eg, neonatal alloimmune thrombocytopenia [NAIT], post-transfusion purpura), gene analysis, common variant, HPA-2a/b (T145M) | 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. | XS | Separate structure, a service that is distinct because it was performed on a separate organ/structure |
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| 2018-01-01 | Added | Code Added. |
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