Variation among instruments in interference by cephalosporin in the Jaffé reaction for creatinine.

errors ofmetabolism currently depends on sophisticated biochemical analysis. NMR analysis can simultaneously analyze the mixture of compounds in biological fluids, but complete analysis of biological fluids by NMR will not be necessitated. Accurate diagnosis should await the results by authenticated methods. Quickness is important. As might be seen from our paper, the need to pretreat urine to compensate for the signals of glycerol is only applicable to glyceroluria, which is very rare. Our method will be used for solected cases for clinical use; it should suffice for clinical screening. NMR analysis of freeze-dried (and redissolved in DM80) samples of biological fluid had not been reported. Wilson and Nicholson reported the absence of a signal of urea in the conventional method, but detected it in the freezedriedJDMSOsolution. This phenomenon is well known and is not new. Both the careful clinician’s eye and . the quick screening of biological fluid will afford several important pieces of information that one would not be able to get by using only a higher magnetic field NMR spectrometer. Comparisons ofthe ability ofvarious N.MR machines is not a usual goal for researchers, I