Related Experiment Videos
Urine hydroxyproline: a potential error in quantification and a proposed procedure for its measurement
J E Buttery1, S Stuart, D J Gee
1Department of Clinical Chemistry, Queen Elizabeth Hospital, Woodville, South Australia.
Pathology
|January 1, 1991
Summary
A modified hydroxyproline assay using external standards underestimates results due to color suppression in urine. Using an internal standard for each urine test corrects this, ensuring accurate hydroxyproline measurements.
Area of Science:
- Biochemistry
- Clinical Chemistry
- Analytical Chemistry
Background:
- The colorimetric method by Bergman and Loxley is used for measuring urinary hydroxyproline.
- Accurate hydroxyproline quantification is crucial for diagnosing certain metabolic bone diseases.
Purpose of the Study:
- To describe a modification of the Bergman and Loxley colorimetric assay for urinary hydroxyproline.
- To evaluate the accuracy and precision of the modified assay using external hydroxyproline standards.
Main Methods:
- A modified colorimetric assay for urinary hydroxyproline was developed, utilizing external aqueous standards.
- Color development suppression in urine samples was investigated.
- Internal standards were incorporated into the assay protocol to correct for suppression.
Main Results:
- The modified assay with external standards underestimated urinary hydroxyproline by an average of 32% due to color suppression.
- Incorporating an internal standard for each urine sample corrected for this suppression, yielding an average recovery of 99%.
- The overall imprecision of the corrected assay was less than 5%, with linearity up to 1500 mumol/L.
Conclusions:
- The modified colorimetric assay for urinary hydroxyproline requires the use of internal standards to accurately account for color development suppression in urine.
- This corrected method provides a reliable and precise assay for clinical use.