New blood test comes out tops

According to a recent study, a new blood test for kidney function, Cystatin-C, may be a better predictor of death and cardiovascular risk among the elderly than the standard measure.

The study, funded by the National Heart, Lung, and Blood Institute (NHLBI), appeared in the May 19 issue of the New England Journal of Medicine.

More than 4,000 senior adults participated in the study comparing Cystatin-C and the standard test, creatinine, as predictors of death from all causes, death from cardiovascular causes, and incidence of heart attack and stroke.

The results showed that Cystatin-C, a more sensitive test, distinguishes those at low, medium and high cardiovascular risk and may enable earlier detection.

It is estimated that 20 million Americans have significantly reduced kidney function, and that even a small loss of kidney function can double a person’s risk of developing cardiovascular disease.

Both creatinine and Cystatin-C are proteins found in the blood and filtered through the kidneys. When the kidneys are not working well, these proteins accumulate in the blood, which provides a signal to the doctor that a person may have kidney disease. Because creatinine is a by-product of muscle cell metabolism, its levels in the blood can be affected by factors other than kidney disease, such as age, gender, race and lean muscle mass. Cystatin-C is produced by blood cells, and its levels in the blood are not impacted by these factors.

( National Heart, Lung, and Blood Institute, a division of the U.S. Department of Health and Human Services)