Phenothiazine Derivatives in Urine: "False Nagative Results" With the Forrest Color Test (FPN), and a Method for Their Elimination

[摘要] More than 100 Forrest color tests (FPN) were performed on urine specimens from patients taking phenothiazine drugs. The results obtained showed > 20% "false negatives" and 6% "false positives." A delayed reaction due to possible individual patient variation seems to have been the cause for false-negative results. These false negatives were shown to disappear when test readings were delayed for 1-5 min. Some false positives were due to liver dysfunction.

[学科分类] 过敏症与临床免疫学