Reference values and analytical performance of the hydroxyproline/creatinine ratio in early morning urine samples.

The hydroxyproline/creatinine ratio for two groups of healthy individuals and two groups of patients with a history of mammary and prostatic carcinoma without metastases was measured and compared with literature values. The hydroxyproline/creatinine ratio for healthy adults appears to be 1.4 (range 0.7--2.3). Furthermore, the influence of diet and gelatin load of 30 g on the hydroxyproline creatinine ratio and the hydroxyproline excretion has been investigated. The analytical characteristics of the test used in the present study were evaluated using the method of standard additions. An intra-assay quality-control on the basis of the standard addition is proposed. The coefficient of variation of the hydroxyproline/creatinine ratio appears to be 22%. The intraindividual variability has also been established for the hydroxyproline/creatinine ratio and appears to be 25%.