CPT codes form the standardized language used by healthcare providers and payers to describe medical procedures and services for billing and tracking. CPT code 87635 specifically identifies a highly advanced type of infectious disease testing. This code relates to the laboratory detection of a single, specific respiratory pathogen using a molecular method.
Decoding the Specific Code
CPT 87635 is defined as “Infectious agent detection by nucleic acid (DNA or RNA); severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (Coronavirus disease [COVID-19]), amplified probe technique.” This descriptor indicates the test looks for the genetic material of the virus that causes COVID-19. The code was rapidly established to allow for the tracking and billing of this specific, high-volume test.
The core method described by this code is a Nucleic Acid Amplification Technique (NAAT), often called an “amplified probe technique.” This molecular approach contrasts with simpler, non-amplified tests like rapid antigen screens. The specificity of this code distinguishes it from broader CPT codes that cover panels designed to detect multiple respiratory pathogens simultaneously. Code 87635 focuses on the detection of SARS-CoV-2 and any pan-coronavirus types or subtypes present in the sample.
The Science Behind the Test
The technology underpinning CPT 87635 is a Nucleic Acid Amplification Test (NAAT), most commonly Reverse Transcription-Polymerase Chain Reaction (RT-PCR). This method begins by isolating the genetic material, which is RNA for SARS-CoV-2, from a patient’s sample, such as a nasopharyngeal swab. The extracted RNA is then converted into a more stable DNA form, which is necessary for amplification.
The power of NAAT lies in its ability to exponentially increase the amount of this specific genetic sequence. Specialized chemical primers and probes locate the target DNA sequence unique to SARS-CoV-2. Over multiple cycles, the process creates millions of copies of the target genetic material.
This amplification process gives the test superior sensitivity and specificity compared to older diagnostic techniques. Traditional methods, like viral cultures, require days for the virus to grow to a detectable level. The molecular amplification used in 87635 allows for a reliable result from minute quantities of genetic material, often providing a definitive diagnosis within hours.
Clinical Applications of the Procedure
The primary clinical use of the procedure reported by CPT 87635 is the definitive diagnosis of acute COVID-19 infection. Its high accuracy makes it the gold standard for confirming the presence of the virus in symptomatic patients. Specimens are typically collected from the upper respiratory tract, such as a nasopharyngeal swab, and processed in a clinical laboratory.
The rapid turnaround time of this molecular test is essential for clinical decision-making. Quickly confirming a COVID-19 diagnosis allows providers to initiate appropriate supportive care and targeted antiviral treatments. A swift result also guides public health measures, enabling immediate patient isolation to prevent community transmission.
This test is valuable because COVID-19 symptoms, such as fever, cough, and fatigue, overlap significantly with other common respiratory illnesses, including influenza and RSV. Obtaining a definitive molecular diagnosis of SARS-CoV-2 helps the clinician differentiate between these infections. This distinction ensures the patient receives the correct management, avoiding the unnecessary use of medications like antibiotics for a viral infection.
Understanding the Billing Implications
CPT code 87635 serves as the standardized identifier for this molecular testing service on a medical claim form. The American Medical Association (AMA) created this code to streamline the reporting and reimbursement process. It ensures that when a laboratory performs the SARS-CoV-2 NAAT, commercial insurance payers receive a consistent description of the service provided.
The actual cost of the test can vary based on several factors, including the laboratory performing the service and the patient’s insurance coverage. When a claim is submitted, the insurance payer (commercial or government) determines the reimbursement rate for the service. Coverage is typically provided for medically necessary diagnostic testing.
The final amount a patient might owe depends on their insurance plan’s design, including deductibles, co-pays, and co-insurance requirements. The billing process must distinguish between facility charges, which cover the costs of the hospital or clinic where the sample was collected, and professional fees for the laboratory’s technical analysis. This code acts as a crucial link in the financial chain, connecting the complex molecular procedure to a clear, reimbursable service.