CPT® Code 87533

The CPT® Code 87533 refers to a laboratory test designed for the detection of the infectious agent known as human herpes virus-6 (HHV-6) through the analysis of nucleic acids, specifically DNA or RNA. HHV-6 is a virus that can lead to various health issues, particularly in children and immunocompromised individuals. There are two variants of this virus: HHV-6A, which is primarily associated with roseola infantum in children, and HHV-6B, which can cause a mononucleosis-like illness in those with weakened immune systems. The primary infection in children may manifest through symptoms such as fever, rash, and seizures, while reactivation of the virus can lead to more severe symptoms, including fever, lymphadenopathy (swollen lymph nodes), pneumonitis (lung inflammation), hepatitis (liver inflammation), and encephalitis (brain inflammation). The test utilizes a direct probe method to identify the unique nucleic acid sequence of the HHV-6 organism, if present in blood or cerebrospinal fluid (CSF) samples. This method involves the use of a probe that is labeled with either fluorescent or chemiluminescent markers. The sample undergoes treatment to release nucleic acids from the target organism, allowing the labeled probe to specifically bind to the matching target sequence, forming a stable hybrid. Ribosomal RNA is often the focus of this detection process due to its abundance in microorganisms, as it is typically present in thousands of copies compared to the limited copies found in genomic DNA. To enhance the sensitivity of the assay, an amplified probe technique may be employed, which significantly increases the number of target sequences of HHV-6 DNA or RNA through exponential amplification, resulting in millions of copies. The polymerase chain reaction (PCR) or reverse transcriptase polymerase chain reaction (RT-PCR) are the most commonly used amplification techniques. Following amplification, the replicated sequences are identified using labeled DNA probes. The quantification aspect of this test, as indicated by CPT® Code 87533, provides an assessment of the quantity of microorganisms present by utilizing quantitative or real-time PCR. This method allows for the amplification of the isolated nucleic acid segment and generates reports at each stage to document the absolute or relative amounts of the known nucleic acid sequence, thereby offering valuable information regarding the viral load in the sample.