Table 6.
Summary of SMD values for AE assay
| Subgroup | N | SMD (95% CI) | Test(s) of heterogeneity | Significance test(s) of SMD = 0 | P a | |||
|---|---|---|---|---|---|---|---|---|
| I2 (%) | P | Z | P | |||||
| Overall | 16 | 0.79 (0.53–1.05) | 74.5 | 0.000 | 5.97 | 0.000 | ||
| Four experiments excluded | 12 | 0.75 (0.57–0.93) | 26.5 | 0.184 | 8.19 | 0.000 | ||
| Geographic areas | ||||||||
| Asia | 3 | 0.50 (0.15–0.85) | 2.3 | 0.359 | 2.77 | 0.006 | 0.026 | |
| North America | 7 | 0.81 (0.39–1.22) | 74.2 | 0.001 | 3.80 | 0.000 | ||
| Europe | 6 | 0.92 (0.48–1.36) | 80.8 | 0.000 | 4.08 | 0.000 | ||
| Storage method | ||||||||
| Cryopreservation | 2 | 0.20 (−0.11–0.52) | 0.0 | 0.425 | 1.27 | 0.204 | < 0.001 | |
| Fresh | 14 | 0.89 (0.63–1.15) | 69.3 | 0.000 | 6.73 | 0.000 | ||
| Preparation method | ||||||||
| No preparation | 10 | 0.82 (0.50–1.13) | 63.1 | 0.004 | 5.14 | 0.000 | 0.023 | |
| Swim up | 4 | 0.57 (0.20–0.94) | 53.6 | 0.091 | 3.04 | 0.002 | ||
| Discontinuous gradient | 2 | 1.07 (−0.10–2.25) | 95.1 | 0.000 | 1.79 | 0.074 | ||
| FR cut-off value combined with AE assay method | ||||||||
| ≥ 70% vs. < 70% | Spectrophotometry | NC | ||||||
| Spectrophotometry/BAPNA | 1 | 0.86 (0.30–1.41) | –b | – | 3.03 | 0.002 | ||
| ≥ 50% vs. < 50% | Spectrophotometry | |||||||
| Spectrophotometry/BAPNA | 2 | 0.94 (0.18–1.71) | 72.5 | 0.056 | 2.41 | 0.016 | ||
| > 50% vs. = 0% | Spectrophotometry | |||||||
| Spectrophotometry/BAPNA | 1 | 0.82 (0.26–1.38) | – | – | 2.87 | 0.004 | ||
| > 0% vs. = 0% | Fluorometry | |||||||
| PAb-acrosin | 1 | 1.68 (1.29–2.07) | 8.45 | 0.000 | ||||
| PAb-hyaluronidase | 1 | 0.48 (0.13–0.82) | 2.68 | 0.007 | ||||
| MAb 4D4-proacrosin | 2 | 0.72 (0.32–1.13) | 0.0 | 0.600 | 3.50 | 0.000 | ||
| Spectrophotometry | ||||||||
| Spectrophotometry/BAPNA | 2 | 1.23 (−0.74–3.19) | 93.5 | 0.000 | 1.22 | 0.221 | ||
| Accu-Sperm spectrophotometry/BAPNA | 5 | 0.70 (0.41–0.99) | 22.5 | 0.271 | 4.70 | 0.000 | ||
| Spectrophotometry/BAEE | 1 | −0.04 (−0.72–0.64) | – | – | 0.12 | 0.908 | ||
SMD standardized mean difference, CI confidence interval, BAPNA N-α-benzoyl-dl-arginine-p-nitroanilide, BAEE N-benzoyl-l-arginine ethyl ester, NC not compared
aComparison between subgroups with the Q test for heterogeneity
bNot calculated