Components of biological, including seasonal, variation in hematological measurements and plasma fibrinogen concentrations in normal humans

Abstract

This study has been carried out in order to examine the components of biological and, in particular, seasonal variation in hematologic measurements in normal humans. Toward this end, 26 normal volunteers had monthly blood samplings during one calendar year for determination of number of red blood cells (RBC) and platelets, hemoglobin (Hb), hematocrit (Ht), mean corpuscular volume (MCV), MC Hb (MCH), MC Hb concentration (MCHC), RBC distribution width (RDW), mean platelet volume (MPV), platelet distribution width (PDW), plateletcrit (PCT), and plasma fibrinogen concentrations. The data were analyzed by means of spectral analyses of a group of time series or a single time series, and by means of repeated measures analyses of variance. Most of the hematologic variables show seasonal rhythms, such as annual rhythms or harmonics, which are expressed as a group phenomenon. An important part of the variance ( > 15%) in Ht, MCV, MCH, MCHC, RDW, number of platelets, MPV and plasma fibrinogen was explained by a yearly variation. The peak-trough differences (expressed as a percentage of the mean) in the yearly variations in number of RBC, Ht, MCV, MCH, MCHC and RDW were very low (all < 8.5%). Number of platelets (14.4%) and plasma fibrinogen values (28%) showed a high-amplitude yearly variation. All hematological variables, except MCHC, show a high interindividual variability which exceeds by far the intraindividual variability.

Biological Variations of Hematologic Parameters Determined by UniCel DxH 800 Hematology Analyzer

“…Another possibility would be that because the study investigated the changes at only 3 daytime points each day for a 3-day period, some changes, such as seasonal variations, might not have been observed. 3,5 Interestingly, the biological variations during the similar time points (from 9:00 AM-3:00 PM) were also small in that study 5 compared with our study (from 8:00 AM-4:00 PM). The numbers from two 9:00 AM points were also similar, suggesting smaller interday variation.…”

“…[2][3][4][5][6][7][8][9] Some parameters, such as hemoglobin or reticulocytes, have been demonstrated to exhibit hour-to-hour, day-to-day, or seasonal intraindividual fluctuation. 3,6 We revisit these areas for several reasons. First of all, we use the newest model of automated hematology analyzer, UniCel DxH 800 (Beckman Coulter, Inc, Fullerton, California).…”

“…Second, almost all the reported studies in the past have been based entirely on Caucasian/white populations. [2][3][4][5][6][7][8][9] There is little knowledge about biological variation of hematologic parameters among Asian populations. Third, many new hematologic parameters have become available from modern automated hematology analyzers in recent years.…”

Heterogenous vasodilator pathways underlie flow-mediated dilation in men and women

“…While it is possible that blood viscosity may have changed throughout the repeated infusion trials, this is unlikely due to the published intraindividual stability of blood viscosity (36) as well as the small total volume of infusate.…”

Influence of the month of the year in the hematological profile in carthusian broodmares

“…Normal cell physiological processes, body composition, water and food intake, organ function, and diseases are subjected to periodic variations related to biological rhythms in a number of species, including human beings and horses [1][2][3][4]. Oscillations sustained with a period of about one day are called circadian rhythms, which are superimposed upon rhythms with lower frequencies, called infradian rhythms.…”