Chemistry Testing on Plasma Versus Serum Samples in Dialysis Patients: Clinical and Quality Improvement Implications

Plasma samples collected in tubes containing separator gels have replaced serum samples for most chemistry tests in many hospital and commercial laboratories. Use of plasma samples for blood tests in the dialysis population eliminates delays in sample processing while waiting for clotting to complete, laboratory technical issues associated with fibrin formation, repeat sample collection, and patient care issues caused by delay of results because of incompletely clotted specimens. Additionally, a larger volume of plasma is produced than serum for the same amount of blood collected. Plasma samples are also acceptable for most chemical tests involved in the care of patients with ESRD. This information becomes very important when United States regulatory requirements for ESRD inadvertently limit the type of sample that can be used for government reporting, quality assessment, and value-based payment initiatives. In this narrative, we summarize the renal community experience and how the subsequent resolution of the acceptability of phosphorus levels measured from serum and plasma samples may have significant implications in the country's continued development of a value-based Medicare ESRD Quality Incentive Program.