Evaluation of specificity of the modified urinary ketone body test strip

• Published in: Japanese Journal of Medical Technology Vol. 63; no. 5; pp. 586 - 589
• Main Authors: MATSUKI, Miki, TAKEMURA, Hiroyuki, UENO, Tsuyoshi, WAKITA, Mitsuru, KUNO, Yutaka, HORII, Takashi, TABE, Yoko, OHSAKA, Akimichi
• Format: Journal Article
• Language: Japanese
• Published: Japanese Association of Medical Technologists 25.09.2014
• Subjects: Bucillamine; false positive; ketone bodies; modified UROPAPER ALPHA 3 ‘Eiken’ ketone test strip
• ISSN: 0915-8669; 2188-5346
• DOI: 10.14932/jamt.13-106

To test for urinary ketone bodies, test strips based on sodium nitroprusside reaction are routinely used. However, the sodium nitroprusside reaction method frequently shows a false positive result owing to a nonspecific reaction with sulfhydryl (SH)-containing reagents including Bucillamine, an antirheumatic drug. Recently, the modified UROPAPER ALPHA 3 “Eiken” ketone test stripTM (Eiken Chemical, Japan), a urinary test strip that reduces nonspecific reactions, has been developed. In this study, the clinical usefulness of this modified urinary ketone body test strip was evaluated by comparing it with the conventional test strip UROPAPER ALPHA 3 “Eiken” test stripTM using 292 clinical samples from patients. The concordance rate of these two methods was 89.4% (261/292), and there were 31 (10.6%) unmatched samples. Twenty-five of the 31 unmatched samples showed negative results in the modified UROPAPER ALPHA 3 test and positive results in the conventional UROPAPER ALPHA 3 test. The 31 unmatched samples were finally confirmed to be negative for ketone bodies by an enzyme assay. The unmatched samples were obtained from RA patients treated with Bucillamine. In conclusion, the modified UROPAPER ALPHA 3 “Eiken” ketone test stripTM effectively reduced nonspecific reactions caused by the SH-group drug Bucillamine, enhancing the effectiveness of routine urinary tests by increasing the specificity of detecting ketone bodies.