Dilution conditions and standardization study for semen samples using computer-aided sperm analysis / 临床检验杂志

ABSTRACT

Objective To explore the dilution conditions and standards in detecting the semen samples with high sperm concentration using computer-aided sperm analysis(CASA)systems.Methods CASA systems with 10 μm depth disposable counting chambers were used for the examination.The samples were divided into undiluted group(Group 1∶sperm concentration＜50×106/mL)and diluted groups(Group 2∶50×106/mL≤ sperm concentration＜100× 106/mL;Group 3∶sperm concentration≥100× 106/mL).When sperm concentration＜50×106/mL,no dilution was performed.When sperm concentration≥50× 106/mL,the samples were diluted with saline at 1∶n/(50×106)ratio(n=sperm concentration,n/[50×106]rounded down)to＜50×106/mL of sperm concentration.The sperm concentration,progressive motility(PR),non-progressive motility(NP),total motility(PR+NP)and immotile sperm percent-age(IM)were analyzed before and after dilution.The consistency of results pre-and post-dilution was compared.ROC curve was used to analyze the optimal dilution threshold.Results The differences in the parameters pre-and post-dilution gradually rosed with the increased sperm concentration.ROC curve analysis showed optimal dilution thresholds were 133.05 × 106/mL,101.75 × 106/mL,118.60×106/mL,90.90×106/mL,111.83×106/mL for the sperm concentration,PR+NP,PR,NP and IM respectively.Considering sperm concentration and NP were most affected the undiluted high concentration samples,the optimal comprehensive dilution threshold was determined as 125.08× 106/mL.Conclusion When sperm concentration exceeds 125×106/mL,it is recommended to dilute semen sample with normal saline.