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Diurnal variation of von W illebrand factor in plasma: the B ispebjerg study of diurnal variations
Author(s) -
Timm Annette,
Fahrenkrug Jan,
Jørgensen Henrik L.,
Sennels Henriette P.,
Goetze Jens P.
Publication year - 2014
Publication title -
european journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.904
H-Index - 84
eISSN - 1600-0609
pISSN - 0902-4441
DOI - 10.1111/ejh.12298
Subject(s) - diurnal temperature variation , variation (astronomy) , chemistry , atmospheric sciences , physics , astrophysics
Abstract Background Quantitation of von Willebrand factor ( VWF ) in plasma is a central element in assessing von W illebrand disease ( VWD ). VWF activity is known to vary, which has partly been ascribed to biological and preanalytical variation. However, a possible diurnal expression of VWF has not been thoroughly tested. Objectives We examined whether VWF antigen and VWF activity in plasma display a diurnal profile in healthy young males, and whether such variation is related to changes in release or elimination. Methods Plasma from 20 healthy young males was collected at 9 time‐points over 24 h (15 h of light and 9 h of darkness); the plasma concentration of melatonin was used as an internal control to confirm the normal 24‐h rhythms of the individual participants. Results The data, analyzed by rhythmometric statistics, revealed a significant variation ( P = 0.02) and total amplitude of 22.6% in VWF antigen concentrations over the 24‐h period. A pronounced variation in VWF activity was also observed, although not significant according to the 24‐h statistical model. To examine whether the diurnal pattern was related to changes in elimination or secretion, the ratio between (i) coagulation factor VIII and VWF and (ii) VWF propeptide and VWF was determined. Taken together, the data suggest changes in release and not in clearance. Conclusions Diurnal variation in von Willebrand antigen and activity in plasma represents an important aspect of the biological variation. Standardized time‐of‐day plasma sampling for quantitation of VWF in VWD patients seems warranted.