Reviewed by Dr. Oreoluwa Ogunyemi, UrologistCheckmark
Published: April 8, 2017

What Does Necrozoospermia Mean?

Necrozoospermia is the medical term to describe the condition where a low percentage of live sperm and a high percentage of immotile sperm are found in a fresh semen sample. This means that a high percentage of the sperm cells are dead.

According to the World Health Organization, the percentage of live sperm should be greater than 58% and anything lower qualifies as necrozoospermia.

Necrozoospermia is also known as necrospermia.

FertilitySmarts Explains Necrozoospermia

Healthy and mobile sperm are important for fertility as after ejaculation, they must be able to travel to the egg for the purpose of fertilization. If many of the sperm present in semen are dead, it becomes unlikely that the sperm will reach the egg and fertilization will not occur.

How is necrozoospermia assessed?

The number of live sperm is assessed during a semen analysis in two ways:

  1. The dye exclusion method (Eosin–nigrosin staining technique): The damaged membranes found in dead cells are permeable to a colored dye whereas live cells are not.
  2. The hypo-osmotic swelling test: live cells swell when exposed to hypotonic solutions, whereas dead cells do not

What causes necrozoospermia?

Necrozoospermia may be caused by a number of issues including:

  • An infection in the male reproductive tract
  • Chronic medical conditions and toxin exposures.
  • Anti-sperm antibodies (an inflammatory process where the immune system attacks the sperm cells)
  • Advancing age

Necrozoospermia and False-Diagnosis

The quality of a sperm sample (and the number of dead sperm) can be impacted by:

  • The lubricant used while masturbating.
  • Method of semen collection, including the condom used and the container used for storage.


If a semen analysis indicates all sperm are dead, testicular sperm extraction (TESE) with intracytoplasmic sperm injection (ICSI) is a treatment option. This involves taking sperm cells directly from the testicles and injecting one directly into an egg.



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