en Other Other Original Article Original Article <p style="text-align: justify;">Semen analysis, sperm DNA fragmentation (SDF) and hypo-osmotic swelling test (HOST) are usually performed for the evaluation of sperm fertilizing ability. There are some debates over the necessity of SDF and HOST incorporation in male infertility work-up.Semen of 77 men was evaluated by SDF and HOST through three semen analyses. Sperm parameters were arranged into different categories: <5%, 5-15%, >15% for normal morphology; <50%, 50-70%, >70 % for motility; and <10, 10-20, 21-34, 35-50, >50 million/ml for concentration. SDF analysis was performed and values under 30% were assumed to be normal. Normal range of HOST was considered to be >60%.Only normal sperm morphology had significant relationship with DF rate (P<0.001). Normal morphology, motility, and concentration of sperms had significant relationship with HOST (P<0.001, 0.05, and <0.003,respectively). There was a significant negative correlation between sperm morphology and DF rate. The correlations between sperm parameters and percentage of HOST were significantly positive (r: 0.44, 0.19, and 0.32 for morphology, motility, and concentration, respectively). Receiver operating characteristic curve (ROC) showed that sperm morphology is a strong predictor of the rate of DF and HOST (accuracy: 0.74&sbquo; and 0.81, respectively). The best sperm morphology cut off point for DF and HOST rate prediction was 4.5% and 5.5%, respectively.Sperm morphology had significant correlation with DF rate and HOST and is supposed to be a predictor for these tests. Performing these three tests collectively for evaluation of semen samples would not be necessarily required in all cases.</p> Semen analysis, morphology, DNA fragmentation, hypo-osmotic swelling test, IVF 246 254 http://ijmcmed.org/browse.php?a_code=A-10-871-1&slc_lang=en&sid=1 Samaneh Hasanzadeh Keshteli samane.hassanzade@ymail.com 10031947532846008715 10031947532846008715 No Department of Anatomical Sciences, School of Medicine, Babol University of Medical Sciences, Babol, Iran. Mir Mehrdad Farsi mfarsica@gmail.com 10031947532846008716 10031947532846008716 Yes Department of Anatomical Sciences, School of Medicine, Babol University of Medical Sciences, Babol, Iran. Soraya Khafri khafri@yahoo.com 10031947532846008717 10031947532846008717 No Department of Biostatistics and Epidemiology, Babol University of Medical Sciences, Babol, Iran.