What are the indications for Y chromosome microdeletion testing?

[Verified against AUA/ASRM Male Infertility Guideline 2021] Indication. Karyotype and Y-chromosome microdeletion analysis should be recommended for men with primary infertility and azoospermia, or severe oligozoospermia under 5 million sperm/mL, with elevated FSH, testicular atrophy, or a presumed diagnosis of impaired sperm production as the cause (Expert Opinion). Y microdeletions are the second most common known genetic cause of male infertility. Why the result changes what you do, not just what you say: Complete AZFa and/or AZFb deletion — sperm have NOT been retrieved by testicular sperm extraction in these men. The guideline states surgical intervention is not indicated. Testing before offering micro-TESE spares a futile operation. AZFc deletion — sperm may be present in the ejaculate in some men, and are retrieved by TESE in at least 50%. This is the clearest example in male infertility of a genetic test that determines surgical candidacy rather than merely informing counselling. It should therefore precede any discussion of retrieval, not follow a failed attempt. Karyotype alongside: the commonest abnormality is Klinefelter syndrome, where rare foci of spermatogenesis are found on micro-TESE in at least 50–60% of 47,XXY men. Klinefelter is not a contraindication to retrieval. Inheritance counselling: a man with an AZFc deletion who conceives via ICSI will transmit the deletion to all male offspring, who will have the same fertility problem. This should be discussed before treatment. Reviewer: confirm whether a more recent AUA/ASRM update exists — the verified source is 2021.