Abnormalprincipalpiecesnfrsmn

Published: August 9, 2026Updated: August 16, 2026

This test evaluates the structure of sperm tail principal pieces in a semen sample to assess male fertility potential.

Quick summary

{"The test examines sperm tail structure for abnormalities that may affect fertility","Abnormal principal pieces can reduce sperm mobility and fertilizing ability","Results help doctors diagnose male factor infertility causes","The test uses a semen sample, not blood serum","Treatment options are available based on findings"}

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC: 90046-4
Short code: SPZM
Synonyms: Abnormal principal pieces NFr Smn
Category: chemistry
Sample: serum
Container: Sterile wide-mouthed specimen container (non-toxic, non-lubricated)
Units: N/A
Ref low: 0
Ref high: 20
Fasting: false
Population: adult
Sex: male
Age range: ≥ 18 years
Method: Microscopic examination using computer-assisted semen analysis (CASA) or manual microscopy with stained smears
CPT: 89310
SNOMED: 236435004
Specimen volume: Complete ejaculate, preferably 2-5 mL
Stability: Specimen should be delivered to laboratory within 60 minutes of collection. Maintain at room temperature (20-37°C) during transport. Liquefaction occurs within 20-30 minutes at room temperature.
Hemolysis max: 500
Lipemia max: 1000
Icterus max: 500
TAT: 24–72 hours
Order: routine

What is this test?

The Sperm Principal Piece Analysis is a specialized component of a semen analysis that examines the mid-section (principal piece) of sperm tails. The principal piece is the longest part of the sperm tail and is crucial for proper sperm movement. This test uses microscopy to evaluate whether the principal pieces have normal structure or show abnormalities such as irregular thickness, bending, or structural defects.

How is the test performed?

A semen sample is collected, typically through masturbation after 2-5 days of sexual abstinence. The sample is then analyzed under a microscope by a trained technician or using automated analysis systems. The laboratory evaluates the percentage of sperm with abnormal principal pieces compared to those with normal structure. The sample type is semen, not serum as sometimes listed in error.

What do the results mean?

Results are typically reported as the percentage of sperm with abnormal principal pieces. Lower percentages of abnormalities indicate better sperm quality. Your doctor will interpret these results alongside other semen analysis parameters including sperm count, motility, and morphology to provide a complete picture of male fertility health.

Reference range

Reference range: <20% abnormal principal pieces (morphology assessment). Normal morphology indicates <4% abnormal forms according to WHO 2010 criteria.N/A

Specimen: serum

Patient should abstain from sexual activity for 2-5 days before sample collection. Avoid alcohol, caffeine, and smoking for several days prior. Collect specimen via masturbation into a clean, sterile, wide-mouthed container provided by the laboratory. Do not use lubricants or condoms. Deliver specimen to laboratory within 1 hour of collection. Keep specimen at body temperature during transport.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings2

Frequently asked questions

Is the sample type really serum?

No, despite what may be listed in some systems, this test uses a semen sample, not blood serum. The semen sample is collected specifically for analyzing sperm characteristics. If you have questions about sample collection, ask your healthcare provider for specific instructions.

How should I prepare for this test?

Your doctor will typically advise 2-5 days of sexual abstinence before collecting the sample. Avoid alcohol, caffeine, and smoking for several days before the test as these may affect results. Inform your doctor about any medications you are taking, as some can affect sperm quality.

Are abnormal results always a sign of infertility?

Not necessarily. While significant abnormalities in principal pieces can contribute to infertility, many men with mild abnormalities can still father children naturally. The results are interpreted alongside other fertility factors and your overall health situation.

Can abnormal principal pieces be treated?

Treatment depends on the underlying cause. Options may include lifestyle changes (weight loss, quitting smoking, reducing alcohol), treating infections, surgery for varicoceles, or assisted reproductive technologies. Your fertility specialist can recommend the most appropriate approach based on your specific situation.

How long does it take to get results?

Results are usually available within a few days to a week, depending on the laboratory. Your doctor will schedule a follow-up appointment to discuss the results and their implications for your fertility treatment plan.

Sources

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy