Performance of the Technicon "Chem I" system for estimating high-density-lipoprotein cholesterol.

ments suggest that at physiological concentrations, only urate contributes to the artifactually high pre-dialysis values. When a standard serum sample was increased in concentration (in vitro) from 11.6 to 54 mmol/L in urea, from 97 to 1130 mmol/L in creatinine, and from 0.31 to 1.38 mmol/L in urate, values for apparent SFA were unaffected by urea or creatinine changes, but rose 13% in the presence of the additional urate. However, in vivo, there was no direct correlation between the extents of urate and SFA reduction, suggesting that other interfering compounds also contribute to the discrepancy. Among nondialyzable compounds suspected are carbamylated proteins produced by cyanate (5). We conclude that urate and other compounds artifactually increase SFA values in renal-disease patients. During hemodialysis, apparent SFA decreased in 75% of patients tested, sometimes by >20%. Both these facts should be taken into account when the SFA test is used to monitor glycemic control.