Ac. Verhoeven et al., Reliability of spot samples for assessment of urinary excretion of pyridinoline in patients with rheumatoid arthritis, CLIN EXP RH, 19(1), 2001, pp. 78-80
Objective
To determine haw well a spot urine sample of patients with active rheumatoi
d arthritis (RA) can predict 24-hour urinary pyridinoline and deoxypyridino
line excretion
Methods
Urine samples of 11 hospitalized RA patients taken an 2 consecutive days at
8 a.m. and 4 p.m. were compared with samples from 24-hour collections (gol
d standard). High-performance liquid chromatography was used to measure the
collagen crosslink concentrations.
Results
Sampling time was the only significant factor (repeated measurement ANOVA).
Significant differences were found between morning and 24-hour samples and
between morning and afternoon samples, but not between afternoon and 24-ho
ur samples.
Conclusions
Samples collected in the afternoon (4 p.m) give the best approximation of 2
4-hour urinary pyridinoline excretion in patients with active rheumatoid ar
thritis. In longitudinal studies the sampling rime should be fixed.