Summary
Platelet function has been evaluated by Hellem’s original method in carefully screened
normal persons of various ages. Factors which could possibly influence platelet behaviour,
such as drugs, smoking, hypercholesteremia, prediabetes, hypertension or uremia were
excluded in preliminary examinations. Only individuals in perfect health without a
history of coronary heart disease, peripheral vascular disease or other thrombotic
disorders were selected. Physical activity did correspond to the age. Variation in
results possibly due to technical factors were eliminated by using strictly the same
method and material throughout the study and by performing the tests within a relatively
short period of time. From an original group of 109 normal persons, 70 individuals
between the ages of 10 and 90, who corresponded to the described standards were chosen
for further trials. They were divided into 7 age groups, each including 10 individuals
within a decade (the last group ranging from 70 to 90 years). Retention of platelets
in a column of glass beads was measured by Hellem5s method. The results, expressed as per cent retention and represented graphically,
form a parabolic curve with its minimum at the age of 35 (mean ± 2 SD = 50 i 22%).
The mathematical function of the curve can be expressed in a formula as second degree
polynomial. It is shown by analysis of variance that age is the only factor on which
the slope of the curve depends. Physiological or pathological implications of these
findings are not known. The results, however, show that age must be taken into account
when differences of platelet behaviour are discussed.