Severe oligozoospermia refers to a sperm concentration that is markedly lower than the reference range, rather than only mildly reduced. It is more likely to be linked to a hormonal, genetic, obstructive or varicocele-related cause than a mild reduction, so evaluation often includes hormone testing, scrotal ultrasound and sometimes genetic tests such as karyotype or Y-chromosome microdeletion testing. ICSI is commonly used when severe oligozoospermia is present because it needs only a small number of sperm per egg, but the underlying cause is still worth investigating where possible, including for genetic counselling relevant to future children.
Also known as: very low sperm count, cryptozoospermia-range count
Sources
- World Health Organization (who.int)
- ICMR Standard Treatment Workflows (icmr.gov.in/standard-treatment-workflows-stws)
Last reviewed: 9 September 2026. Written by the Antega Editorial Team. General information only — always follow the advice of your own clinic, doctor or pharmacist.