Guideline Non-Adherence in AZFb Microdeletion Diagnostics: A Systematic Review with Two Illustrative Clinical Cases

Background/Objectives: Complete AZFb microdeletions contraindicate testicular sperm retrieval, whereas partial deletions may preserve spermatogenesis. EAA/EMQN guidelines mandate extension analysis to distinguish them, but routine adherence remains unquantified. We audited guideline compliance in published literature and illustrated the findings in two clinical cases. Methods: PubMed and Scopus were searched from inception to August 2026. Eligible studies reported AZFb-deleted men with detectable sperm. Methodological quality was appraised using JBI checklists; data were synthesized narratively. Adherence was assessed against EAA/EMQN guidelines. Two clinical cases served as separate illustrative cases. Results: From 3,416 records, 5 studies (5 patients) and 2 illustrative cases were included. When assessed against the applicable EAA/EMQN guideline version, 1 of 5 included studies (20.0%; 95% CI 0.5–71.6%) was adherent; 4 of 5 (80.0%; 95% CI 28.4–99.5%) were non-adherent. Limitations include the small sample size and reliance on explicitly reported markers. The protocol was registered retrospectively on OSF (DOI: 10.17605/OSF.IO/U5G68). Conclusions: Among the selected reports, 4 of 5 studies were non-adherent to the guideline version in force. “Complete AZFb” diagnoses based solely on basic markers must be considered provisional, especially when spermatozoa are detected, to prevent the irreversible denial of microsurgical testicular sperm extraction.