Table 1. Summary of intra-laboratory and inter-laboratory correlation coefficients (r), coefficient of variation (CV), and intra- and inter-observer variation (%) for SDF assays.
| Methods | Intra-lab (r) | Intra-lab (CV) | Inter-lab (r) | Inter-lab (CV) | Intra-observer variation | Inter-observer variation | Study |
|---|---|---|---|---|---|---|---|
| TUNEL; benchtop flow cytometer | 0.75–0.956 | 0.1–5.7% | 0.83–0.937 | 0.2–5.2% | NR | NR | Ribeiro et al., 2017 |
| TUNEL; benchtop flow cytometer | NR | NR | NA | NA | ≤3%4 | ≤1.7%5 | Sharma et al., 2016 |
| TUNEL; standard flow cytometry | NR | NR | NA | NA | 3.2%2 | 4%3 | Sharma et al., 2010 |
| SCD* | 0.91 | NR | NA | NA | 1%9 | 0.21%10 | McEvoy et al., 2014 |
| SCD | NR | NR | NA | NA | 6–12%8 | 6–12%8 | Fernandez et al., 2005 |
| SCSA | NA | NA | 0.90 | ≤1% | NA | NA | Giwercman et al., 2003 |
| SCSA | NR | 1.0–9.1%1 | NA | NA | NA | NA | Giwercman et al., 1999 |
*, Halosperm G2 test kit. 1, Intra-assay CV varied between 1.0% and 9.1%, and the corresponding values for the inter-assay CV was 5.2% and 8.6%. 2, when absolute values were calculated, 80.0% of individual TUNEL measurement differed from the final designated values by no more than 3.2% (absolute difference); 57.1% of individual measurements in these data had a percentage difference less than 10% of the assigned value. 3, the absolute difference between an observer's designated value and the mean among 2 observers was within 4.0% in 83.3% of specimens; in 83.3% of the specimens, the percentage difference between an individual observer's designated TUNEL value and the 2 observers' average value was within 15%. 4, a single TUNEL measurement from a given observer was within that observer’s average measurement by an absolute difference of 3% or less in 90% of cases. 5, the average TUNEL measurement from a given observer was within the two observers’ average measurements with an absolute difference of 1.73% or less in 80% of cases. 6, correlation between duplicate readings obtained in each laboratory (results from two participating laboratories). 7, correlation coefficient between two participating laboratories reading the same set of specimens. 8, coefficient of variation for the estimated percentage of spermatozoa with fragmented DNA. 9, the average difference in the values of SDF between the two replicates was 1.02%±0.55% (absolute variation); the average percentage difference between the two replicates for each sample was 4.16%. 10, the average difference in the values of SDF between two technicians for each sample was 0.21%±0.57% (absolute difference); the average percentage difference between the two technicians for each sample was 9.56%. TUNEL, terminal deoxyribonucleotide transferase-mediated dUTP nick-end labeling) assay; SCD, sperm chromatin dispersion test; SCSA, sperm chromatin structure assay; NR, not reported; NA, not applicable; CV, coefficient of variation.