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Three types of resin columns for determining serum thyroxine (T 4 ) were evaluated in this study. There were two types of commercial columns and the third type was a column prepared in our laboratory. The three types of columns produced significantly different results when compared after the initial use and when compared after regeneration and subsequent usages. In general, the laboratory columns were equal or superior to those obtained commercially. For large volume users, the preparation of one's own columns and their regeneration and reuse can represent a worthwhile economy.

A turbidimetric test for hemoglobin S and other sickling hemoglobins has been adapted to the Auto-Analyzer. This procedure utilizes the lack of solubility of sickling hemoglobins in a phosphate buffer reagent. It is inexpensive and the results are comparable to those of other screening tests.

Serum glucose measurements were performed on paired specimens from patients with uremia, before and after dialysis, to evaluate the automated glucose oxidase, ortho-toluidine, ferricyanide, and copper reduction methods. All methods were found to yield results statistically different from those of the glucose oxidase method whether glucose was measured before or after dialysis. Before dialysis, the mean difference between the ortho-toluidine and glucose oxidase method results was −9.0 mg. per dl., and after dialysis it was −2.8 mg. per dl.; other methods differed more from glucose oxidase. The glucose oxidase method yielded 2 mg. per dl. or less for uremic sera depleted of glucose by yeast; other methods were less specific for glucose. High uric acid concentrations depressed ortho-toluidine values. Fructose caused slight elevations in ortho-toluidine and large elevations in ferricyanide values. In view of the above findings, the glucose oxidase method is the method of choice for determining glucose values in patients with uremia. Results from 379 nonuremic sera determined simultaneously by the ortho-toluidine and ferricyanide methods were also compared. In nonuremic patients, serum fructose elevation after glucose ingestion partially accounts for the differences between the results of the ortho-toluidine and the ferricyanide methods observed.