RT Journal
A1 Irving CC, Lefkovits AM
T1 MEthods for determination of urinary oxypurines
JF JAMA
JO JAMA
YR 1969
FD March 3
VO 207
IS 9
SP 1716
OP 1716
DO 10.1001/jama.1969.03150220132025
UL http://dx.doi.org/10.1001/jama.1969.03150220132025
AB To the Editor:— 
    We believe that the method described for the determination of urinary oxypurines (205: 213, 1968) is sufficiently accurate for most purposes.The method reported by Klinenberg et al1 is more specific, therefore, more accurate. However, to say that the two methods are not similar is a matter of semantics (206: 1576, 1968). The methods are similar in the sense that each involves the determination of the amount of uric acid formed by oxidation of oxypurines (xanthine + hypoxanthine) in urine upon addition of xanthine oxidase. The greater accuracy obtained by Klinenberg is achieved at the expense of more time and labor.The term "significant error" needs to be defined for a given set of conditions. Applying Klinenberg's data for the relative increases in absorbance at 292 nanometers (nm) due to the oxidation of xanthine and hypoxanthine by xanthine oxidase to our data, one can calculate that the