Evaluation for four reagent kits and two flame photometers used to determine sodium and potassium in serum.

The Stanbio and Medi-Chem sodium and po. tassium kits were evaluated and the results compared with those obtained with the Coleman Jr. Model 21, NIL 4-7000, and Technicon flame photometers. Day-to.day reproducibility studies and data based on comparative studies with sera from patients revealed that the Stanbio and Medi-Chem sodium kits and the Medi-Chem potassium kit give diagnostically unsatisfactory results. Results with the Stanbio potassium kit were reproducible, but further improvement is required, as indicated by nonspecificity in the analyses of patient sera. Instability of the Coleman Jr. flame photometer made it difficult to obtain acceptable data in these tests, particularly for sodium, while the NIL flame photometer had good precision and accuracy.