Simple Tests
摘要
The cyanide nitroprusside test determines the presence of free sulfhydryl or disulfide compounds in urine samples [1–3]. During the first step of the assay, cyanide reduces any disulfides that are present in free sulfhydryl compounds. In the second step, a reddish color reaction results when the free sulfhydryl groups complex with nitroprusside. A positive result is most usually due to cystine in the urine. Familial cystinuria is among the most common aminoacidurias. Disulfides are also excreted in other metabolic disorders such as homocystinuria and β-mercaptolactate-cysteine disulfiduria. Both will also produce positive results according to the following reaction: RSH + Na2Fe(CN)5NO (sodium nitroprusside) → chromophore + NO.