CPT® Code 83500

Hydroxyproline is classified as a non-protein amino acid that is predominantly found in collagen, a vital protein that provides structure and strength to various tissues in the body, including skin, bones, and cartilage. The measurement of hydroxyproline levels can be significant in diagnosing and monitoring certain medical conditions. Elevated levels of hydroxyproline may indicate pathological conditions such as Paget's disease, which involves abnormal bone remodeling, bone metastatic cancer, where cancer spreads to the bones, hyperparathyroidism, a condition characterized by excessive parathyroid hormone production leading to increased calcium levels, osteoporosis, a disease that weakens bones, or glucocorticoid excess, which can affect bone metabolism. Although hydroxyproline testing can serve as a non-specific marker for bone resorption, it is important to note that newer and more specific tests are now available. The testing process for hydroxyproline involves measuring free hydroxyproline levels in the blood, which requires a blood specimen obtained through venipuncture. This specimen undergoes quantitative analysis using high-performance liquid chromatography (HPLC) on blood plasma or serum. Additionally, hydroxyproline levels can also be assessed through urine testing, where patients must adhere to a collagen-free diet for 72 hours prior to urine collection. A 24-hour urine specimen is then collected and analyzed using colorimetric methodology. Furthermore, the total hydroxyproline in urine can be evaluated under CPT® Code 83505, which also necessitates the same dietary restrictions and collection methods.