CPT® Code 87652

The CPT® Code 87652 refers to a laboratory test designed for the detection of the infectious agent known as Streptococcus, group A (GAS) through the analysis of nucleic acids, specifically DNA or RNA. This test is crucial for identifying the presence of GAS, which is primarily transmitted via respiratory droplets and direct contact with infected skin lesions, such as those seen in impetigo. Additionally, there have been instances of transmission through contaminated food and water. The clinical manifestations of GAS infections are diverse, commonly presenting as respiratory illnesses and skin infections, but they can also lead to more severe conditions such as meningitis, osteomyelitis, toxic shock syndrome, and necrotizing fasciitis. The testing process involves a direct probe test, which utilizes a specific nucleic acid sequence known as the target sequence of the GAS bacterium. This sequence is identified if it is present in the respiratory or other biological samples. The probe used in this test is labeled with either fluorescent or chemiluminescent markers, allowing for precise detection. The sample undergoes treatment to release nucleic acids from the target organism, if it exists, and the labeled probe selectively binds to the matching target sequence, forming a stable hybrid. In many cases, ribosomal RNA is the focus of detection due to its abundance in microorganisms, often existing in thousands of copies compared to the limited 1-2 copies found in genomic DNA. The sensitivity of the assay can be significantly enhanced through an amplified probe technique, which involves exponentially multiplying the target sequence of GAS DNA or RNA into millions of copies. The polymerase chain reaction (PCR) or reverse transcriptase polymerase chain reaction (RT-PCR) are the most commonly employed amplification methods. Following amplification, the replicated sequences are identified using labeled DNA probes. The quantification aspect of this test, as indicated by CPT® Code 87652, provides an assessment of the number of microorganisms present in the sample, often utilizing quantitative or real-time PCR to amplify the isolated nucleic acid segment and generate a detailed report documenting the absolute or relative amounts of the known nucleic acid sequence.