[Internal quality control of sperm concentrations in semen analysis: establishment of a method]

To establish a method for internal quality control (IQC) of sperm concentration test in the laboratory.

We set the concentrations of frozen semen at 20 x 10(6) and 80 x 10(6) as low and high concentrations of putative IQC products, with QC-BEADSTM quality control beads (QCBs) as the control. Using the double-blind method, four technicians determined the sperm concentrations of the IQC products and QCBs by computer-assisted sperm analysis, and drew a quality control chart (Xbar chart and Sbar chart) for each product. Through a month of continuous detection, we calculated and compared the intra- and inter-batch coefficients of variation (CV%) of the quality control products of high and low concentrations.

The intra-batch coefficients of variation of the assumed IQC products of high and low concentrations were CV3.5% and CV2.4%, and their inter-batch coefficients of variation were CV10.2% and CV9.6%. The intra-batch coefficients of variation of the QCBs of high and low concentrations were CV5.1% and CV7.1%, and their inter-batch coefficients of variation were CV7.1% and CV8%. The intra-batch coefficients of variation of both IQC products and QCBs of high and low concentrations were <10%, and their inter-batch coefficients of variation were <15%, which conformed to Levey-Jennings quality control principles and achieved IQC purposes. No significant differences were found in either intra- or inter-batch coefficients of variation between the IQC products and QCBs of high and low concentrations (P>0.05), indicating that assumed IQC products can replace QCBs for internal quality control in the laboratory.

The IQC method we established for determining sperm concentration is simple, feasible and reliable.