[Seasonal variation of blood components important for diagnosis (author's transl)]

In a comparative study, the differences between the values measured for 26 blood and serum components in both winter and summer were determined in 78 healthy subjects. Comparable conditions during the preparation of test persons, sampling, processing of specimens, and measurement were strictly observed. The term "season" is defined more precisely by meterological data. In the summer season, significantly higher values were found for leukocytes (9%), lactate dehydrogenase and MCHC (7% each), creatinine (7%, in women only), and MCH (1%) whereas significantly lower values were exhibited by aspartate aminotransferase (18%), alanine aminotransferase (14%), alkaline phosphatase (11%), glucose and packed cell volume (7% each), MCV (6%), total protein (2%), erythrocytes, albumin, sodium and chloride (1% each). These partly considerable alterations should be taken into account in the establishment of reference values and evaluation of laboratory findings (above all, when intraindividual comparison is involved). There were no significant alterations of the following parameters: hemoglobin, gamma-glutamyl transferase, urea, uric acid, creatinine (men only), bilirubin, cholesterol, total glycerol, potassium, calcium, and inorganic phosphate. In another series of experiments involving 32 test persons, the influence of different ambient temperatures during blood sampling on the above mentioned blood components was studied. Within the 18-30 degrees C range, no significant alterations were detected.