The investigation was made on the determination method of serum uric acid by the Beckman Glucose Analyzer which catches, by polarograpic oxygen electrode, the consumption speed of oxygen consumed in proportion to the concentration of uric acid when it is oxydized by uricase, and the following results were found:
1. The standard curve passing through the original point was straight up to 12mg/dl concentration of uric acid and showed tendency of more or less curving down at the higher concentrations.
2. Accuracy given by simultaneous determination (n=10) was ±3.0% in C. V. at the normal values of serum uric acid and was ±2.2% at the higher values. The daily variation (n=10) on pool serum was satisfactorily ±3.6% in C. V.
3. The recovery rate on this method was from 97.4 to 101.3% with an average of 99.5%.
4. Glucose, cystine and phenol did not show any influence on the deter mination values, whereas 100mg/dl of ascorbic acid showed positive error of 1.3mg/dl as uric acid and 10mg/dl of formaldehyde showed negative error of 0.4mg/dl as uric acid.
5. The change of the reaction temperature between 30°C and 40°C had no influence of the determination values.
6. The enzyme reagent mainly composed of uricase was endurable for at least five time use.
7. The determinations by this method on the uric acid values of eighty serum samples from patients gave the sufficiently satisfactory coefficients of correlation (γ), 0.950, by phosphotungstic acid method and, 0.910, by uricase catalase photometric method. The average values of the uric acid determinations of these samples were 5.3mg/dl by uricase catalase photometric method, 5.4mg/dl by this method and 6.0mg/dl by phosphotungstic acid method. The determinations by this method on the uric acid values of forty urine samples from patients gave also the adequately satisfactory coefficients of correlation (γ), 0.946, by phosphotungstic acid method and, 0.918, by uricase catalase photometric method. The average values of these determinations were 57.7mg/dl by uricase catalase photometric method, 60.0mg/dl by this method and 73.9mg/dl by phosphotungstic acid method.
Conculusion
It is conclusively considered from the above results that this is the method to determine the real values of uric acid, with small amount of sample, speedily and simply with high reproducibility and therefore that this is one of the most excellent methods at present to determine the serum uric acid.
View full abstract