# name
The time of blood sampling for osteocalcin determinations.

# metadata.dc.description.abstract[].value
Sir: We have read the interesting article by
Pietschmann et al about the serum osteocalcin
concentrations in patients with rheumatoid
arthritis.' In their work there was no mention
of the time at which blood samples were taken
for osteocalcin determination.
Several studies have shown a circadian
rhythm of serum osteocalcin in normal adults,
with peak values during the night and a nadir
during the morning hours.2 3 Therefore, in
our opinion, if osteocalcin is used as a marker
in clinical investigations of bone metabolism it
is important to mention the time at which
blood was collected for its measurement.
Otherwise, interpretation of results may be
difficult and comparison with values obtained
in other studies impossible.

# metadata.dc.relation.ispartof[].value
Annals of the Rheumatic Diseases, 1990, vol. 49, núm. 2, p. 133

# metadata.dc.source[].value
Articles publicats en revistes (Ciències Clíniques)

# metadata.dc.title[].value
The time of blood sampling for osteocalcin determinations.