Table 4.
ROC curve analysis for age and standard semen parameters. Criterion variable is SDF level >18%.
| Parameter | AUC | SE | CI 95% | Suggested Optimal Cut-Off Point |
|---|---|---|---|---|
| Age (y) | 0.601 ** | 0.021 | 0.563–0.638 | 32.00 |
| Semen volume (mL) | 0.506 | 0.022 | 0.468–0.545 | 6.00 |
| Sperm concentration (×106/mL) | 0.641 ** | 0.021 | 0.603–0.677 | 13.80 |
| Total number of spermatozoa (×106) | 0.625 ** | 0.021 | 0.587–0.661 | 27.75 |
| Morphologically normal spermatozoa (%) | 0.740 ** | 0.018 | 0.705–0.772 | 2.00 |
| TZI | 0.677 ** | 0.020 | 0.641–0.713 | 1.52 |
| Sperm progressive motility (%) | 0.746 ** | 0.018 | 0.711–0.778 | 50.00 |
| Eosine-negative spermatozoa—live cells (%) | 0.743 ** | 0.018 | 0.708–0.775 | 74.00 |
| HOS test-positive spermatozoa—live cells (%) | 0.743 ** | 0.019 | 0.706–0.777 | 71.00 |
| Peroxidase-positive cells (mln/mL) | 0.567 | 0.021 | 0.529–0.605 | 0.00 |
AUC—area under the curve; ** Statistical significance with AUC = 0.5 at p < 0.001; CI 95%—95% confidence interval; HOS test—hypo-osmotic swelling test; ROC—receiver operating characteristic; SDF—sperm DNA fragmentation; TZ—teratozoospermia index. The levels of AUC were as follows: 0.9–1.0—excellent predictive value; >0.8–0.9—good predictive value; >0.7–0.8—satisfactory predictive value; >0.6–0.7—moderate predictive value; and 0.5–0.6—insufficient predictive value.