How To Use CPT Code 81108

CPT 81108 describes the genetic analysis procedure known as Human Platelet Antigen 4 genotyping (HPA-4), specifically analyzing the ITGB3 gene. This article will cover the description, official description, procedure, qualifying circumstances, appropriate usage, documentation requirements, billing guidelines, historical information, similar codes and billing examples.

1. What is CPT Code 81108?

CPT 81108 is a genetic analysis procedure that focuses on the Human Platelet Antigen 4 (HPA-4) genotyping. It involves analyzing the ITGB3 gene, specifically looking for the common variant HPA-4a/b (R143Q). This test is commonly used to assess the risk or aid in the diagnosis of conditions such as neonatal alloimmune thrombocytopenia (NAIT), post-transfusion purpura (PTP), and thrombocytopenia.

2. Official Description

The official description of CPT code 81108 is: ‘Human Platelet Antigen 4 genotyping (HPA-4), ITGB3 (integrin, beta 3 [platelet glycoprotein IIIa], antigen CD61 [GPIIIa]) (eg, neonatal alloimmune thrombocytopenia [NAIT], post-transfusion purpura), gene analysis, common variant, HPA-4a/b (R143Q).’

3. Procedure

1. The lab analyst performs the technical lab test to analyze the genes of the two common alleles of Human Platelet Antigen 4 (HPA–4), also called R143Q, using a specimen such as blood or amniotic fluid.
2. The lab analyst performs all technical steps, including extracting nucleic acids, amplifying the gene, and detecting the target genes using methods such as polymerase chain reaction (PCR) and fluorescence markers.
3. The test specifically focuses on the ITGB3 gene and identifies the HPA–4 antigen alleles in the patient specimen.
4. The analysis determines the patient’s HPA–4 antigen genotype, which can help assess the risk or aid in the diagnosis of conditions such as neonatal alloimmune thrombocytopenia (NAIT), post–transfusion purpura (PTP), and thrombocytopenia.

4. Qualifying circumstances

CPT 81108 is commonly ordered by clinicians to assess the risk or aid in the diagnosis of conditions such as neonatal alloimmune thrombocytopenia (NAIT), post–transfusion purpura (PTP), and thrombocytopenia. It is used to identify the patient’s HPA–4 antigen genotype for fetuses or neonates with suspected NAIT, assess pregnancy risk for parents or prospective parents who have had an affected pregnancy, or aid in the diagnosis of potential transfusion reactions in patients exhibiting PTP.

5. When to use CPT code 81108

CPT code 81108 should be used when there is a clinical need to assess the risk or aid in the diagnosis of conditions related to the HPA–4 antigen genotype. It is specifically used for the genetic analysis of the ITGB3 gene and the identification of the common variant HPA–4a/b (R143Q).

6. Documentation requirements

To support a claim for CPT 81108, the documentation should include:

• Reason for ordering the test and the clinical need
• Specific details of the genetic analysis procedure performed
• Identification of the HPA–4 antigen genotype
• Relevant clinical information and indications for the test
• Signature of the lab analyst performing the test

7. Billing guidelines

When billing for CPT 81108, ensure that the test is performed by a qualified lab analyst and that the documentation supports the clinical need for the test. It is important to distinguish CPT 81108 from other HPA genotype tests described by different codes in the range 81105–81112. If the ordering clinician requests physician interpretation of the test, an additional code such as G0452 with modifier 26 may be reported.

8. Historical information

CPT 81108 was added to the Current Procedural Terminology system on January 1, 2018. There have been no updates to the code since its addition.

9. Examples

1. A clinician orders CPT 81108 to assess the risk of neonatal alloimmune thrombocytopenia (NAIT) in a pregnant patient with a history of affected pregnancies.
2. A patient with a suspected transfusion reaction undergoes CPT 81108 to aid in the diagnosis of post-transfusion purpura (PTP).
3. A clinician orders CPT 81108 to assess the risk of thrombocytopenia in a patient with unexplained low platelet count.
4. A neonate with suspected neonatal alloimmune thrombocytopenia (NAIT) undergoes CPT 81108 to determine the HPA–4 antigen genotype.
5. A clinician orders CPT 81108 to assess the risk of thrombocytopenia in a patient with a family history of the condition.
6. A patient with a suspected transfusion reaction undergoes CPT 81108 to aid in the diagnosis of post-transfusion purpura (PTP).
7. A clinician orders CPT 81108 to assess the risk of neonatal alloimmune thrombocytopenia (NAIT) in a pregnant patient with a history of affected pregnancies.
8. A patient with unexplained low platelet count undergoes CPT 81108 to determine the HPA–4 antigen genotype.
9. A clinician orders CPT 81108 to assess the risk of thrombocytopenia in a patient with a family history of the condition.
10. A neonate with suspected neonatal alloimmune thrombocytopenia (NAIT) undergoes CPT 81108 to determine the HPA–4 antigen genotype.