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The CPT® Code 81112 refers to the gene analysis for Human Platelet Antigen 15 (HPA-15) genotyping, specifically focusing on the common variant HPA-15a/b, which is associated with certain medical conditions such as neonatal alloimmune thrombocytopenia (NAIT) and post-transfusion purpura. This procedure involves the identification of specific genetic variants that can impact platelet function and immune response. The HPA-15 gene encodes for a protein known as CD109, which is a molecule found on the surface of platelets. Variants in this gene can lead to the development of platelet alloantigens, which occur due to single nucleotide polymorphisms (SNPs) that alter the genes coding for platelet membrane glycoproteins. The analysis is particularly significant in clinical scenarios involving symptomatic neonates, where it can help identify HPA-15 variants that may contribute to NAIT, a condition where maternal antibodies target fetal platelets, leading to severe thrombocytopenia and potential complications such as intracranial hemorrhage. Additionally, this test can be utilized during pregnancy to screen for fetal alloimmunization and assess the risk of NAIT in future pregnancies, as well as to evaluate the risk of post-transfusion purpura in women who have received platelet transfusions containing incompatible HPA or platelet-specific antigens. The testing process typically 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 alleles associated with the HPA-15 variant.
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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 is characterized by severe bleeding that occurs 5-10 days following a platelet transfusion containing incompatible HPA or platelet-specific antigens, necessitating the identification of HPA-15 variants to assess risk.
Fetal Alloimmunization Screening - The test may be performed during pregnancy to screen for fetal alloimmunization, which can inform management strategies for future pregnancies.
Maternal Risk Assessment - The analysis helps assess the risk of NAIT in future pregnancies for mothers who have previously experienced complications related to platelet alloantigens.
Sample Collection - Blood, amniotic fluid, or cultured amniocytes are obtained through a separately reportable procedure. The choice of sample type depends on the clinical scenario and the stage of pregnancy.
Testing Methodology - The collected samples are subjected to multiplex polymerase chain reaction (PCR) techniques. This method utilizes allele-specific primer extensions to amplify the regions of interest in the HPA-15 gene.
Fluorescence Observation - Following amplification, fluorescence observation is employed to detect the presence of specific alleles associated with the HPA-15a/b variants. This step is crucial for determining the genetic makeup of the sample in relation to the HPA-15 gene.
After the completion of the gene analysis, results are typically reviewed and interpreted by a qualified healthcare professional. The findings can provide critical information for managing the patient's condition, particularly in cases of NAIT or post-transfusion purpura. Follow-up care may include monitoring for symptoms associated with these conditions, as well as counseling for future pregnancies if applicable. It is essential to communicate the results to the patient and discuss any necessary interventions or precautions based on the genetic findings.
| Short Descr | HPA-15 GENOTYPING | Medium Descr | HPA-15 GENOTYPING GENE ANALYSIS COMMON VARIANT | Long Descr | Human Platelet Antigen 15 genotyping (HPA-15), CD109 (CD109 molecule) (eg, neonatal alloimmune thrombocytopenia [NAIT], post-transfusion purpura), gene analysis, common variant, HPA-15a/b (S682Y) | 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. |
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| 2018-01-01 | Added | Code Added. |
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