‘Pseudohypouricosuria’ in Alcaptonuria: Homogentisic Acid Interference in the Measurement of Urinary Uric Acid with the Uricase — Peroxidase Reaction

Autor: Kazuya Higashino, Yumiko Nasako, Jun-ichi Yamakita, Zenta Tsutsumi, Hiroyuki Ohata, Yuji Moriwaki, Sumio Takahashi, Tetsuya Yamamoto
Rok vydání: 1999
Předmět:
Zdroj: Annals of Clinical Biochemistry: International Journal of Laboratory Medicine. 36:501-503
ISSN: 1758-1001
0004-5632
DOI: 10.1177/000456329903600414
Popis: Urinary excretion of uric acid was found to be extremely low in a 58-year-old female patient with alcaptonuria. This was due to interference with the uricase-peroxidase method used, because analysis using high-performance liquid chromatography (HPLC) showed a normal urinary concentration of uric acid. In vitro experiments demonstrated that a high concentration of homogentisic acid in the patient's urine inhibited the peroxidase reaction, possibly due to inhibition of the colour development of 3-methyl- N-ethyl- N-(β-hydroxyethyl)aniline (MEHA) and 4-aminoantipyrine, via the peroxidase reaction. A homogentisic acid concentration equivalent to that in plasma did not affect the uricase-peroxidase reaction. This result suggests that any assay based on a peroxidase method is affected by a high urinary concentration of homogentisic acid in patients with alcaptonuria.
Databáze: OpenAIRE
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