CPT® Code 81219

The CPT® Code 81219 pertains to the molecular genetic testing of the CALR (calreticulin) gene, specifically focusing on common variants found in exon 9. This gene analysis is crucial for identifying mutations that may include substitutions, insertions, and deletions within the CALR gene, which is located on the p arm of chromosome 19, specifically between positions 13.3 and 13.2. The testing serves as a diagnostic medical marker for conditions such as essential thrombocytopenia (ET) and primary myelofibrosis (PMF). The CALR gene is responsible for encoding the calreticulin protein, which plays a vital role in various cellular functions, including the processing and transport of calcium ions within the endoplasmic reticulum (ER), as well as influencing gene activity, cell growth, proliferation, migration, adhesion, and apoptosis, which are essential processes in wound healing and immune system function. Mutations in the CALR gene are typically somatic, meaning they are not inherited but rather acquired during an individual's lifetime, occurring in only a subset of cells. These mutations, particularly those involving the addition or deletion of genetic material at exon 9, are notably associated with essential thrombocytopenia, a condition characterized by elevated platelet levels and disruptions in normal blood clotting mechanisms. Additionally, CALR gene mutations can also be present in patients diagnosed with primary myelofibrosis, a serious condition where the normal bone marrow is replaced by fibrotic scar tissue, leading to various hematological complications. The testing process involves obtaining blood and/or bone marrow samples, which are then analyzed for gene mutations using polymerase chain reaction (PCR) amplification and subsequent genetic analysis of the resulting fragments.