Round cells on a semen analysis: normal range and what an elevated result means
Round cells is a catch-all term for cells in the semen that are not sperm. Most are either white blood cells, which suggest inflammation or infection, or immature sperm cells shed from the testicle, which suggest something different. The basic count cannot tell them apart, which is why a raised round cell result usually leads to a second test. This page explains the WHO 2021 threshold of 1 million white cells per mL, how the lab distinguishes the cell types, and what to do with an elevated result.
What your number means
| Normal | under 1 million round cells/mL | Expected. Small numbers of round cells are present in every sample and need no follow-up. |
|---|---|---|
| Borderline | 1 to 2 million round cells/mL, white cell fraction not yet determined | Ask the lab whether the cells were tested with a peroxidase stain. If most are immature germ cells, the finding relates to spermatogenesis rather than infection. If most are white cells, treat as leukocytospermia. |
| Elevated | over 1 million peroxidase-positive white cells/mL | Leukocytospermia by WHO definition. Indicates inflammation somewhere in the genital tract, with or without a bacterial infection. Warrants a semen culture; white cells release reactive oxygen species that damage sperm motility and DNA. |
| Markedly elevated | over 5 million white cells/mL, or visible pus | Pyospermia. Strongly suggests active infection (prostatitis, epididymitis, urethritis, or a sexually transmitted infection). Needs culture, STI testing and treatment before further fertility assessment. |
What it measures
During the concentration count, the lab also counts round cells — any nucleated cell that is not a sperm — in the same counting chamber and reports them per millilitre. They fall into two main groups: leukocytes (white blood cells, mainly neutrophils) that enter the semen from the prostate, seminal vesicles, epididymis or urethra, and immature germ cells (spermatids and spermatocytes) that were released from the seminiferous tubules before finishing development. Epithelial cells from the urethra also appear occasionally.
The two groups look similar under ordinary microscopy but mean different things, so the WHO recommends a peroxidase stain whenever round cells exceed 1 million/mL. Neutrophils contain peroxidase and stain brown; germ cells do not. Some labs use immunocytochemistry for the CD45 leukocyte marker instead, which is more sensitive but less widely available.
Reports vary in what they print. Some show only "round cells"; some show "WBC" estimated from morphology without staining; some show a peroxidase-confirmed leukocyte count. Check which yours is, because a "WBC" value that was not confirmed by staining may be mostly germ cells.
Why it matters for fertility
White blood cells are a marker of inflammation, and inflammation in the male genital tract has two effects on sperm. First, activated leukocytes release large amounts of reactive oxygen species, which damage the sperm membrane, impair motility and increase DNA fragmentation. Second, the infection or inflammation that attracted the white cells may itself be damaging the epididymis or prostate, or partially obstructing the duct system.
The 1 million/mL threshold is a consensus value rather than a percentile of fertile men, and its clinical significance is debated. Some men with leukocytospermia have entirely normal sperm parameters and negative cultures, and some studies find no effect on pregnancy rates. Others find lower motility, higher DNA fragmentation and reduced IVF fertilisation. The practical view is that leukocytospermia is worth investigating, especially when it coexists with low motility, raised DNA fragmentation or symptoms.
Immature germ cells tell a different story. A high proportion of immature cells in the ejaculate indicates that spermatogenesis is being disrupted, with cells released before they mature. This is seen with varicocele, heat stress, toxic exposures and some hormonal problems, and is associated with lower count and motility. It is not treated with antibiotics.
What raises it
Bacterial infection of the prostate, seminal vesicles, epididymis or urethra is the main cause of raised white cells. Common organisms include E. coli and other gut bacteria, Enterococcus, and the sexually transmitted infections Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma and Ureaplasma. Many cases of leukocytospermia, however, have negative cultures and represent sterile inflammation.
Non-infectious causes of leukocytospermia include chronic prostatitis / chronic pelvic pain syndrome, autoimmune reactions, recent urinary tract instrumentation, and heavy smoking, alcohol or cannabis use. Long abstinence increases round cell counts in some men. Varicocele is associated with both leukocytospermia and increased immature germ cells.
Raised immature germ cells reflect a disturbance of spermatogenesis: varicocele, fever or heat exposure in the previous 2–3 months, chemotherapy or radiation, testicular injury, hormonal suppression (including testosterone use) and toxic exposures. They are often seen alongside low count and morphology.
How to improve it
The first step after a raised round cell count is to determine what the cells are. Ask for a peroxidase stain if it was not done, and if white cells are confirmed above 1 million/mL, obtain a semen culture including testing for Chlamydia, gonorrhoea, Mycoplasma and Ureaplasma (often via a urine PCR test).
If a pathogen is found, treat it with the appropriate antibiotic, treat the partner where relevant, and retest. Empirical antibiotics for culture-negative leukocytospermia are commonly prescribed but the evidence that they improve sperm parameters or pregnancy rates is weak; they may modestly reduce white cell counts in some men. Anti-inflammatory medication and antioxidants have been studied for culture-negative cases with mixed results.
For raised immature germ cells, the treatment is directed at the cause of the spermatogenic disturbance: varicocele repair, removing heat exposure, stopping testosterone or other suppressive drugs. For assisted reproduction, sperm preparation techniques (density gradient) remove most round cells and leukocytes from the sample, so their presence does not prevent IUI or IVF.
When to retest
A round cell count over 1 million/mL should be followed by a peroxidase stain and, if leukocytospermia is confirmed, a semen culture, rather than simply a repeat semen analysis. Leukocytospermia is frequently transient, so if the culture is negative and there are no symptoms, a repeat semen analysis after 4–6 weeks with 2–5 days of abstinence is reasonable.
After antibiotic treatment of a confirmed infection, retest at 6–12 weeks. White cell counts usually fall within a few weeks, but improvements in motility and DNA fragmentation take a full spermatogenic cycle.
If white cells stay above 1 million/mL on two samples with negative cultures, and sperm parameters are otherwise normal, further treatment is unlikely to change outcomes and the finding can be noted and monitored. If they coexist with low motility or high DNA fragmentation, a reproductive urology review is worthwhile.
Tests that measure this
Related diagnoses
Common questions
What are round cells on a semen analysis?
Round cells are any cells in the semen that are not sperm. The two main types are white blood cells, which indicate inflammation or infection, and immature sperm cells released from the testicle before finishing development. Small numbers are normal. Above 1 million per mL, the lab should do a peroxidase stain to find out which type predominates, because the two have different causes and different treatments.
Do elevated round cells mean I have an infection?
Not necessarily. Elevated round cells may be immature germ cells rather than white cells, and even confirmed white cells (leukocytospermia) have negative cultures in a large proportion of men, representing sterile inflammation. The next step is a peroxidase stain and, if white cells are confirmed, a semen culture and STI testing. Only a positive culture confirms infection.
Can white blood cells in semen affect sperm?
Yes. Activated white cells release reactive oxygen species that damage the sperm membrane, reduce motility and increase DNA fragmentation. The effect varies between men, and some with leukocytospermia have normal sperm parameters, but when it coexists with low motility or high DNA fragmentation it is worth treating any underlying infection and considering antioxidants.
Will antibiotics fix leukocytospermia?
If a bacterial infection is confirmed on culture, antibiotics treat the infection and usually reduce the white cell count within weeks. For culture-negative leukocytospermia, the evidence that antibiotics help is weak; some men improve, many do not, and the white cells often disappear on their own. Antibiotics are best reserved for cases with a positive culture or clear symptoms.