The effect of diurnal variation on erythrocyte sedimentation rate

Objectives: It has been known that some laboratory tests showed diurnal variation and were affected by fasting-satiety status. We aimed to examine erythrocyte sedimentation rate (ESR) for both pre-analytical factors. Methods: Blood samples from 12 volunteers were taken and studied with the Westergren method. Fasting blood samples taken at 9:00 am were accepted as basal. Samples were taken at 10:00, 11:00, 12:00 were compared with baseline to evaluate fasting-satiety status and samples taken at 12:00, 15:00, 18:00, and 24:00 to evaluate diurnal variation. Results: ESR was found to be the lowest at 09:00 and 15:00 (Median=5.5 mm/h). The 10:00, 11:00, and 12:00 results for assessing fasting-satiety status on ESR were not different than the baseline (6.2, 6.0, and 7.8 mm/h, respectively). The rates at 18:00 and 24:00 were not found to be different than the baseline (5.7 and 6.6 mm/h). Conclusions: We didn't find that ESR had diurnal variation, and it wasn't affected by fasting-satiety status. Although it is known that routine biochemistry tests should be performed from the blood sample taken in the morning in case of starvation, blood sampling can be done for ESR during the day if necessary.