A semen analysis, often called a spermiogram, is a fundamental laboratory test used to assess a male’s fertility potential. This microscopic examination of the ejaculate provides detailed information about the sperm cells and the surrounding fluid. It is widely used in fertility evaluations and to confirm the success of a vasectomy procedure. Understanding the terminology and the numbers on the report is the first step toward interpreting the results and understanding reproductive health metrics.
Preparing for an Accurate Test Reading
The reliability of a semen analysis hinges on proper preparation before the sample is collected. A period of sexual abstinence is necessary, typically requiring two to seven days without ejaculation, to ensure sperm reserves are adequately built up. Abstaining for too short a time can result in an artificially low sperm count, while a period longer than seven days may decrease sperm motility.
The collection method requires the entire sample to be caught in a sterile container, usually through masturbation. Losing even a small portion, particularly the first part of the ejaculate, can skew the results for volume and concentration. If collected outside the laboratory, the sample must be kept at body temperature and delivered for analysis within 30 to 60 minutes to preserve viability. Notify the lab of any recent fevers or illnesses, as these events can temporarily suppress sperm production and lead to unreliable data.
The Three Pillars: Sperm Concentration, Motility, and Total Count
Sperm concentration indicates the number of sperm cells found in each milliliter of semen. The World Health Organization (WHO) sets the lower reference limit at 15 million sperm per milliliter (million/mL). Values below this threshold are noted as reduced concentration, suggesting a lower density of sperm in the ejaculate.
Motility assesses the ability of sperm to move, categorized into different types of movement. Progressive motility (PR) is the most relevant parameter, measuring the percentage of sperm actively swimming forward in a straight line or large circles. For a normal result, at least 32% of the sperm should demonstrate this progressive movement. Total motility includes all moving sperm, even those that are twitching in place or moving in non-linear ways.
The total count represents the absolute number of sperm in the entire sample. It is calculated by multiplying the sperm concentration by the total ejaculate volume. This metric accounts for the entire reproductive contribution, regardless of volume. The lower reference limit for total sperm number per ejaculate is 39 million. An individual may have a concentration slightly below the lower limit, but a high total volume may still result in a normal total sperm count.
Decoding Secondary Parameters: Morphology, Volume, and Fluid Characteristics
Sperm morphology refers to the physical shape and structure of the sperm cells, including the head, midpiece, and tail. This parameter is assessed using strict criteria, such as the Kruger or WHO criteria, which define a sperm as normal only if it meets specific size and shape requirements. Due to this rigorous assessment, the lower reference limit for normal forms is set at 4%.
The ejaculate volume is measured in milliliters, with a lower reference limit of 1.5 mL. Low volume can indicate an issue with collection or a partial blockage in the reproductive tract, such as the seminal vesicles or ejaculatory ducts. Fluid characteristics are also evaluated, including liquefaction, which is when the thick ejaculate turns into a liquid form after collection.
Liquefaction should occur naturally within 15 to 30 minutes at room temperature, and a delay can suggest a problem with the enzymes in the seminal fluid. Viscosity refers to the thickness or stickiness of the liquefied sample; if it remains too thick, it can impede sperm movement. The pH level, which measures the acidity or alkalinity of the fluid, should be greater than 7.2.
Clinical Interpretation: Understanding Normal Ranges and Next Steps
When semen parameters fall below established reference limits, specific clinical terminology describes the findings. Low sperm concentration is termed oligozoospermia, poor progressive motility is called asthenozoospermia, and a high percentage of abnormally shaped sperm is teratozoospermia. The complete absence of sperm in the ejaculate is known as azoospermia.
Semen parameters can fluctuate significantly day-to-day due to short-term factors like stress or minor illness. Therefore, an abnormal result often necessitates a retest, typically performed a few weeks to months later, to confirm the baseline status. If a second analysis confirms abnormal parameters, the next step is generally a referral to a specialist.
A urologist or reproductive endocrinologist can investigate the underlying causes of abnormal findings. Specialists may recommend additional tests, such as hormone blood work or a physical examination, to determine if the issue is hormonal, anatomical, or related to lifestyle factors. An abnormal semen analysis indicates a male factor that may contribute to difficulty conceiving and warrants further medical evaluation.