Semen Analysis – What are normal values?

When considering infertility, both the health of the woman and the man must be considered. The male factor – usually described as mild, moderate or severe – infertility is defined as a deviation from what is normally expected of sperm. These abnormalities are one ore more of the following: the number of sperm present, the proportion of the motile to non-motile (moving) sperm, and/or morphologically normal versus non-viable sperm.

Semen is collected after 2-5 days of abstinence. Analysis of sperm are conducted in a laboratory within 1 hour of collection. Doctors usually require analyses of sperm samples on at least 3 occasions over a 2 month period before conclusively making a diagnosis of an abnormality.

According to the World Health Organization1, the following are the normal values expected in semen analyses when testing the quality of a fertile man’s sperm.

  • Seminal volume: 2.0-5cc
  • Seminal pH: 7.2 – 7.8 (some say up to8.0)
  • Sperm density, AKA sperm count: >20 million/cc or ≥40 million per total ejaculate
  • Sperm motility: ≥50% forward-moving sperm or ≥20% total motile sperm
  • Sperm morphology: ≥30% normal morphology
  • Sperm vitality: ≥75% of sperm are alive
  • Semen liquefaction time: <30 minutes
  • White blood cells (WBC) in semen: <1 million/cc

Since 65% of the volume of ejaculate is produced in the seminal vesicles, low volume is typically associated with the absence or decrease of the seminal vesicle’s contribution to total ejaculate. Additionally, the seminal vesicles contribute alkaline (basic) fluid rich in seminal fructose to the ejaculate. So, overly acidic semen or semen poor in fructose can point to a problem in the seminal vesicles, like a blockage. A blockage in the vas deferens and ejaculatory duct should also be considered.

Overly alkaline semen (generally thought to be pH >8), is typically a sign of infection.

Upon ejaculation, semen is liquid. It later coagulates by protein kinase secreted by the seminal vesicles. After coagulation, enzymes from the prostate begin to work, causing the semen to liquify again. Delayed or absent liquefaction, can indicate a problem in the prostate, like prostatitis. If the semen doesn’t become liquid again, sperm motility will be hindered.

Low sperm sperm count, or oligospermia, is considered to be <20 million/cc and normal sperm count is considered to be >20 million/cc.

Sperm motility, ideally >50% are forward-moving, is evaluated by the following scale:

  • 0 — No movement
  • 1 — Movement, none forward
  • 1+ — Occasional movement of a few sperm
  • 2 — Slow, undirected
  • 2+ — Slow , directly forward movement
  • 3- — Fast, but undirected movement
  • 3 — Fast, directed forward movement
  • 3+ — Very fast forward movement
  • 4 — Extremely fast forward movement

Sperm morphology is the next variable analyzed. This evaluates the shape of the sperm. Sperm are organized into the following categories:

  • normal-oval shaped
  • tapered
  • amorphous
  • duplicated
  • immature

Sperm are considered normal when they have an “oval form with smooth contour, acrosomal cap encompassing 40-70% of head, no abnormalities of midpiece, or tail and no cytoplasmic vacuoles of more than half of the sperm head.”2. Any sperm not strictly fitting the criteria, also known as borderline sperm, are counted as abnormal. The types of abnormality are amorphous, tapered, duplicated, immature, coiled-tail, blunted-tail, or mid-piece.

The presence of some white blood cells (WBC) in ejaculate is normal. When levels of WBCs is >1 million/cc, infection should be suspected. This is called leukocytospermia. Some populations of men can have leukocytospermia without the presence of infection. A doctor should always culture semen to detect anaerobic or aerobic pathogens, including chlamydia and mycoplasma. The reason why the presence of WBCs is undesirable when trying to conceive is WBCs can oxidize sperm, making them non-viable.

Other tests you might want to ask your doctor to run are:

  • Anti-sperm antibodies test
  • Acrosome reaction
  • Hamster egg penetration test
  • Hemizona Assay
  • NAAT-based detection of the pathogens
  • Biochemical markers, like creatine kinase and reactive oxygen species (ROS)
  • Blood test to check hormone levels, specifically testosterone, leutinizing hormone (LH) and follicle stimulating hormone (FSH)
  • Imaging studies to rule out obstruction
  • Post-ejaculation urinalysis to determine if there is retrograde ejaculation
  • Testicular biopsy; usually done as a last resort when diagnosis cannot be determined by other means because it is so invasive

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1. WHO Laboratory manual for the examination of Human semen and Sperm-Cervical mucus interaction. Cambridge University Press, 3rd edition, 1992
2. Stonybrook University Hospital, Department of Urology

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