87535

Infectious agent detection by nucleic acid (DNA or RNA); HIV-1, amplified probe technique

CPT code 87535 represents a highly sensitive laboratory procedure designed to detect the presence of Human Immunodeficiency Virus Type 1 (HIV-1) using a nucleic acid amplified probe technique. This test is generally referred to as an HIV-1 Nucleic Acid Amplification Test (NAAT) or Polymerase Chain Reaction (PCR) test. Unlike traditional serological tests that rely on the detection of antibodies or antigens produced in response to the virus, which can take weeks to appear in the bloodstream during the window period, this assay directly targets and amplifies the genetic material, specifically the RNA, of the HIV-1 virus. The clinical utility of this procedure is multifaceted and critical for accurate infectious disease management. It is predominantly indicated for the early detection of acute HIV-1 infection before seroconversion occurs, effectively narrowing the detection window period to as little as ten to fourteen days post-exposure. Furthermore, it is instrumental in resolving indeterminate, equivocal, or inconclusive results from standard screening algorithms, such as the fourth-generation antigen and antibody combination immunoassays. It is also a critical component in the screening of neonates born to HIV-1 positive mothers, where maternal IgG antibodies can cross the placenta and persist in the infant bloodstream, confounding traditional antibody testing for up to eighteen months. During the procedure, the laboratory professional receives a biological specimen, most commonly blood plasma or serum. The sample is subjected to chemical lysis to disrupt the viral envelope and release the viral nucleic acids into solution. Following extensive extraction and purification steps, specific primers engineered to bind exclusively to highly conserved regions of the HIV-1 genome are introduced to the sample. Using an enzyme known as reverse transcriptase, the viral RNA is converted into complementary DNA (cDNA). A sophisticated thermocycling process, such as polymerase chain reaction, transcription-mediated amplification, or nucleic acid sequence-based amplification, then exponentially amplifies the target DNA sequence. Fluorescently labeled oligonucleotide probes bind to these amplified sequences, emitting a measurable signal that confirms the presence of the virus. A positive result indicates active and current HIV-1 infection. It is vitally important for medical coders and providers to note that this specific code is qualitative in nature, meaning it is only designed to detect the presence or absence of the virus. It should strictly not be confused with CPT code 87536, which is designated for the quantification or viral load testing of HIV-1.

Clinical Indications

  • Suspected acute HIV infection (acute retroviral syndrome) prior to seroconversion.
  • High-risk exposure to HIV-1 (e.g., needle-stick injury, high-risk sexual encounter) within the window period.
  • Indeterminate, equivocal, or conflicting results from initial HIV antigen/antibody immunoassays.
  • Diagnosis of HIV-1 infection in infants born to HIV-seropositive mothers to rule out passive transfer of maternal antibodies.
  • Screening of blood, organ, and tissue donors to ensure the safety of the donor supply.

Procedure Steps

  1. Specimen collection, typically venous blood, followed by centrifugation to obtain plasma or serum.
  2. Addition of a chemical lysis buffer to the biological specimen to disrupt viral envelopes and release nucleic acids.
  3. Extraction and purification of viral RNA using specialized laboratory kits or automated nucleic acid extraction platforms.
  4. Addition of a master reaction mix containing reverse transcriptase, DNA polymerase, nucleotides, specific HIV-1 primers, and fluorescent probes.
  5. Reverse transcription of viral RNA into complementary DNA (cDNA).
  6. Exponential amplification of the target DNA sequence using a thermocycling method such as PCR or TMA.
  7. Detection of the amplified viral targets through continuous real-time fluorescence monitoring.
  8. Data analysis comparing the fluorescence signal against assay controls to determine the qualitative presence or absence of HIV-1.
  9. Generation and verification of the final diagnostic report by the laboratory director or qualified pathologist.

Coding Guidelines

  • Code 87535 is for qualitative amplified probe technique only. Do not use for quantification (viral load); use 87536 for quantification.
  • Do not report 87535 in conjunction with 87534 (direct probe technique) for the same patient specimen.
  • If testing for HIV-2 is concurrently performed via amplified probe, use CPT code 87538 in addition to 87535.
  • Ensure the test is performed in a CLIA-certified laboratory appropriate for high-complexity testing.
  • Medical necessity documentation must link to high-risk exposure, symptomatic presentation, or indeterminate prior testing if routine screening limits are exceeded.

Associated ICD-10 Codes