What are the latest guidelines for evaluating severe oligozoospermia?

[Verified against AUA/ASRM Male Infertility Guideline 2021] Semen analysis interpretation. Results are of greatest clinical significance when multiple abnormalities are present (Expert Opinion). With the exception of azoospermia, complete globozoospermia, necrozoospermia and complete asthenozoospermia — which clearly cause infertility — no individual parameter is highly predictive of fertility or diagnostic of infertility. The odds ratio for infertility rises as the number of abnormal parameters increases. Counsel on the pattern, not on one number. Genetic testing. Karyotype and Y-microdeletion for severe oligozoospermia under 5 million/mL with elevated FSH, testicular atrophy, or presumed impaired sperm production (Expert Opinion). Hormonal evaluation. FSH and testosterone are not recommended as first-line tests in all infertile men, but are indicated for impaired libido, erectile dysfunction, oligozoospermia or azoospermia, atrophic testes, or evidence of hormonal abnormality on examination (Expert Opinion). Oligospermia under 10 million/mL is itself an indication. Add LH where testosterone is under 300 ng/dL, and prolactin for hypogonadotropic hypogonadism or reduced libido. Round cells. Where round cells exceed 1 million/mL, further evaluation is needed to distinguish white cells (pyospermia) from germ cells (Expert Opinion). Pyospermia should be evaluated for infection (Clinical Principle). Routine semen culture without pyospermia has not been shown to benefit infertile couples. Not part of initial evaluation: antisperm antibody testing (Expert Opinion) and sperm DNA fragmentation (Moderate Recommendation, Grade C). WHO 6th edition (2021) lower fifth percentile values, from Table 8.3: semen volume 1.4 mL (95% CI 1.3-1.5); sperm concentration 16 million/mL (15-18); total sperm number 39 million (35-40); total motility 42% (40-43); progressive motility 30% (29-31); vitality 54% (50-56); normal forms 4% (3.9-4.0). WHO cautions explicitly that the lower fifth percentile does not represent a limit between fertile and infertile men, and that the manual is not a guideline for clinical decisions. Note also that total sperm number per ejaculate has greater diagnostic value than concentration, provided volume is measured accurately.