Comparative studies on the determination of uric acid with the continuous flow machine, the manual reduction method and the enzymatic color test
Herrmann, W.; Lindhofer, H.G.; Schütz, C.
Zeitschrift für die Gesamte Innere Medizin und ihre Grenzgebiete 33(20): 759-764
1978
ISSN/ISBN: 0044-2542 PMID: 735246 Document Number: 124908
The manual and automatised determination of uric acid by means of phosphotungstic acid as well as the enzymatic test are compared: 1. When the manual reduction method is performed in the deproteinisation losses of uric acid develop (too low pH-value, absorption). For the precipitation of protein the pH-value 3 must not be undercut. Use uranyl acetate (no trichloro-acetic acid). 2. By dialysing of serum the automatized method avoid errors in precipitation. On the other hand, the simultaneous determination of non-uric acid chromogens is valid as for the manual method. Therefore, the automatically established values are higher. 3. Normal regions for the automatized phosphotungstic acid method are: males 4.8--8.2, females 3.5--7.5 mg uric acid/100 ml serum. 4. Comparisons of the quality of the manual and automatized reduction method for the enzymatic colour test are performed: In the precision the methods tested achieve comparable results (VK 2.1--3.5). The investigations of the correctness by means of control sera achieved acceptable results. The enzymatic colour test gives, since scarcely influenced by pharmaca and nearly specifically, the most reliable results. When using reduction methods analytic and preanalytic sources of error (e.g. pharmaca) must vastly be excluded. The automatised reduction method gives the advantage that there do no more appear any losses of uric acid. There is another normal region for the methods tested.