OBJECTIVETo search for a method for the precise measurement of human semen volume so as to provide reliable evidence for clinical semen analysis.

METHODSThe volumes of 492 semen samples collected from 137 donors by Zhejiang Human Sperm Bank were measured respectively by three different methods including electronic balance weighing, volumetric cylinder measuring, and combination of the two methods above. With the combined measuring method, the semen weight was first obtained by electronic balance weighing, then the semen density determined by volumetric cylinder measuring, and lastly the semen volume figured out by a formula. Paired sample t-test was used to compared the combined method with electronic balance weighing and volumetric cylinder measuring.

RESULTSThe mean volume of the 492 semen samples obtained by the combined measuring method was (3.46 +/- 1.17) ml, significantly lower than (3.75 +/- 1.21) ml from electronic balance weighing (P < 0.05) and markedly higher than (3.22 +/- 1.16) ml from volumetric cylinder measuring (P < 0.05). The mean semen density of the 492 samples was (1.0928 +/- 0.0761) g/ml, and the mean weight of the residual semen in the container used in volumetric cylinder measuring was (0.269 +/- 0.122) g.

CONCLUSIONSemen volume measured by electronic balance weighing is higher while that obtained from volumetric cylinder measuring is lower than the actual value. An accurate semen volume can be achieved by the combined measuring method, which, therefore, deserves to be widely used both clinically and in researches.