CPT® Code 82610

Cystatin C is a serum protein that plays a crucial role in assessing kidney function. It is produced by all nucleated cells in the body and is characterized by its low molecular mass, which enables it to be filtered through the glomerular membrane in the kidneys. When a blood sample is obtained for the measurement of cystatin C levels, it provides valuable information regarding the glomerular filtration rate (GFR). This measurement is particularly significant because, under normal circumstances, cystatin C is filtered out of the blood and subsequently reabsorbed and broken down by the body, without being returned to the bloodstream. However, when kidney function is compromised, the filtration process is impaired, leading to an accumulation of cystatin C in the blood. Elevated levels of cystatin C can indicate decreased kidney function and are utilized in the evaluation of glomerular filtration rate, as well as in the screening and monitoring of renal disease. Additionally, cystatin C levels can serve as a prognostic marker following a heart attack, with higher levels correlating with a poorer survival outlook. The measurement of cystatin C is typically performed using a technique known as nephelometry, which allows for precise quantification of this important biomarker.