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The CPT® Code 81105 pertains to the gene analysis of Human Platelet Antigen 1 (HPA-1), specifically focusing on the HPA-1a/b allele variant. This genetic testing is crucial for identifying the presence of the HPA-1a/b variant, which is associated with conditions such as neonatal alloimmune thrombocytopenia (NAIT) and post-transfusion purpura. NAIT is a serious condition that arises when maternal IgG antibodies cross the placenta and target paternally inherited alloantigens present on the fetal platelets, leading to a significant reduction in platelet count, known as thrombocytopenia. Symptoms of NAIT can manifest as severe thrombocytopenia, intracranial hemorrhage, and various forms of bleeding, including petechiae and visceral hemorrhage. On the other hand, post-transfusion purpura occurs when a patient experiences severe bleeding following a platelet transfusion that contains incompatible HPA or platelet-specific antigens. The HPA-1 a/b allele variants are particularly significant, as they are implicated in approximately 80% of severe NAIT cases within the Caucasian population. 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 specific allele variants through fluorescence observation. This gene analysis not only aids in diagnosing affected neonates but also plays a vital role in screening for fetal alloimmunization during pregnancy and assessing the risk for future pregnancies or post-transfusion complications in mothers.
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Neonatal Alloimmune Thrombocytopenia (NAIT) - This condition occurs when maternal antibodies target fetal platelets, leading to severe thrombocytopenia and potential complications such as intracranial hemorrhage.
Post-Transfusion Purpura - This condition is characterized by severe bleeding that occurs 5-10 days after a platelet transfusion containing incompatible HPA or platelet-specific antigens.
Fetal Alloimmunization Screening - The test may be utilized to screen for fetal alloimmunization during pregnancy, helping to identify at-risk pregnancies.
Maternal Risk Assessment - The analysis can assess the risk of NAIT in future pregnancies for mothers who have previously experienced complications related to HPA-1 variants.
Step 1: Sample Collection - Blood, amniotic fluid, or cultured amniocytes are collected as the primary samples for testing. These samples must be obtained through a separately reportable procedure to ensure proper handling and analysis.
Step 2: DNA Extraction - Once the samples are collected, DNA is extracted from the cells present in the samples. This step is crucial for isolating the genetic material needed for the subsequent analysis.
Step 3: Multiplex Polymerase Chain Reaction (PCR) - The extracted DNA undergoes multiplex PCR, a technique that allows for the simultaneous amplification of multiple target DNA sequences. This method is essential for detecting the specific HPA-1a/b allele variants.
Step 4: Allele-Specific Primer Extensions - Following PCR amplification, allele-specific primer extensions are performed. This step involves using primers that are designed to bind specifically to the HPA-1a or HPA-1b alleles, facilitating the identification of the variants present in the sample.
Step 5: Fluorescence Observation - The final step involves observing the results through fluorescence detection. This method allows for the visualization of the amplified products, confirming the presence of the HPA-1a/b variants based on the fluorescence signals generated during the analysis.
After the completion of the gene analysis, results are typically reviewed and interpreted by qualified healthcare professionals. The findings can provide critical information regarding the presence of HPA-1 variants, which can influence clinical decisions and management strategies for affected neonates and their mothers. It is essential to communicate the results to the relevant healthcare providers to ensure appropriate follow-up care and monitoring for any potential complications associated with NAIT or post-transfusion purpura. Additionally, counseling may be offered to the parents regarding the implications of the findings for future pregnancies and the management of any identified risks.
| Short Descr | HPA-1 GENOTYPING | Medium Descr | HPA-1 GENOTYPING GENE ANALYSIS COMMON VARIANT | Long Descr | Human Platelet Antigen 1 genotyping (HPA-1), ITGB3 (integrin, beta 3 [platelet glycoprotein IIIa], antigen CD61 [GPIIIa]) (eg, neonatal alloimmune thrombocytopenia [NAIT], post-transfusion purpura), gene analysis, common variant, HPA-1a/b (L33P) | 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. | GW | Service not related to the hospice patient's terminal condition |
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| 2018-01-01 | Added | Code Added. |
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