A study of 264 men compared blood biochemistry with semen quality and found weak correlations involving magnesium and some other measures.
Statistical significance disappeared after correction for multiple testing, reinforcing the role of semen analysis in male fertility assessment.
Could the routine blood tests taken during a health check reveal sperm motility or the extent of sperm DNA damage?
If certain blood components reflected sperm quality, male fertility assessment could become easier. A recent study, however, found that routine blood biochemical markers could not reliably predict semen quality.
Published in Scientific Reports on October 20, the study compared blood biochemistry and semen-analysis measures in 264 men to investigate possible associations.
Weak correlations appeared between some blood markers, including magnesium, and progressive sperm motility. These associations did not remain statistically significant after adjustment for the errors that can arise when many comparisons are made at once.
The findings suggest that routine blood testing can inform overall health assessment, but evidence is insufficient to use it independently to judge sperm motility or DNA damage.
How might blood biochemistry relate to sperm quality?
Semen analysis is a fundamental test in male infertility evaluation. It directly examines concentration, motility and morphology to assess characteristics relevant to fertilization.
Routine blood tests instead measure biochemical components that reflect metabolism and organ function. Researchers have considered whether these markers might also relate to sperm production or function.
Magnesium, for example, is an essential mineral involved in cellular energy metabolism and enzyme activity. Because sperm movement requires energy, its relationship with motility is worth investigating.
Yet a substance being necessary for normal sperm function is different from its blood concentration being a useful predictor of sperm quality. Clinical use requires a sufficiently strong and consistent relationship.
Weak magnesium–motility correlations did not survive adjustment
In the analysis of 264 men, weak correlations appeared between some blood and semen measures, including magnesium and progressive motility.
Progressive motility means the ability of sperm to move forward. It is important for traveling through the female reproductive tract toward an egg and is a key semen-analysis measure.
However, the observed relationships did not remain significant after statistical adjustment.
Comparing many blood components against many semen measures can produce apparently significant findings by chance. The researchers applied a multiple-testing correction to account for this, and the initially significant associations disappeared.
This does not prove that magnesium has no relationship with sperm movement. It means the study does not support using blood magnesium as a reliable predictor of sperm motility.
Routine blood tests cannot establish sperm DNA integrity
DNA integrity attracts attention alongside sperm movement and shape when evaluating sperm quality.
Sperm DNA fragmentation measures damage to the genetic material within sperm. Some research has suggested associations between increased fragmentation, embryo development after fertilization and pregnancy outcomes.
Normal standard semen results do not necessarily establish normal sperm DNA. DNA damage can be elevated even when concentration, motility and morphology fall within normal ranges.
The present findings are relevant because they did not provide evidence that routine systemic biochemical measures can reliably predict sperm quality.
Normal blood-test results therefore should not be taken as proof that sperm DNA is undamaged. Nor should an abnormal blood component, by itself, be treated as proof of sperm DNA damage.
Blood testing does not replace semen analysis
The central point is that routine blood tests and semen analysis provide different information.
Blood testing is useful for evaluating metabolism and general health. When appropriate, reproductive hormone tests can also help identify endocrine disturbances that affect sperm production.
These tests do not replace direct assessment of sperm number, movement and shape. Sperm DNA fragmentation testing likewise requires separate consideration according to clinical need.
The study’s sample of 264 men calls for cautious interpretation. Failure to find a statistically significant association does not eliminate every possible future use of blood markers. Larger studies should examine specific patient groups and prediction methods combining several markers.
For couples preparing for IVF or ICSI, routine blood results alone cannot establish sperm fertilizing ability or embryo-development potential. Evaluation needs to combine semen findings with medical history, lifestyle, hormonal status and any additional tests that are indicated.
A single blood test that reliably assessed sperm quality would be convenient. This study shows why that possibility requires stronger, reproducible evidence before becoming a clinical test.
Source: This article is based on “Associations between routine systemic biochemical indices and semen quality: a cross-sectional study in men undergoing health examination,” by researchers at Fujian Medical University and Fujian Maternity and Child Health Hospital, China, published October 20, 2026 in Scientific Reports. DOI: 10.1038/s41598-026-76251-z.
Image disclosure: The image was created using generative AI (ChatGPT, OpenAI); any people depicted are fictional, not real individuals.
For background on ovarian reserve, semen analysis and when additional investigations may be considered, see our guide to the first fertility clinic visit.
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