Evaluation of Azoospermia

Initial Diagnostic Approach

The initial evaluation for azoospermia should include a physical examination performed by an examiner with appropriate training and expertise, a reproductive history, and at least two properly performed semen analyses, as recommended by the European Association of Urology 1
Perform at least two semen analyses at least one month apart to confirm azoospermia, with patients abstaining from sexual activity for 2-3 days before collection, and specimens kept at room or body temperature during transport and examined within one hour of collection, according to the American Academy of Family Physicians 2
Assess for presence of vasa deferentia, as congenital bilateral absence can be diagnosed by physical examination, and check for varicocele, hydrocele, or other scrotal abnormalities, as recommended by the American Urological Association 2, 3
Evaluate secondary sex characteristics, including hair distribution and breast development, and perform digital rectal examination to assess prostate, as part of a comprehensive physical examination, according to the American College of Physicians 2

Hormonal Evaluation

Measure serum testosterone and follicle-stimulating hormone (FSH) levels, as FSH levels are negatively correlated with the number of spermatogonia, and consider measuring luteinizing hormone (LH) as part of basic hormonal workup, as recommended by the European Society of Endocrinology 2, 3
Some experts recommend anti-Müllerian hormone (AMH) testing as lower levels may predict better sperm retrieval outcomes, according to the American Society for Reproductive Medicine 3

Distinguishing Obstructive vs. Non-obstructive Azoospermia

Low ejaculate volume (<1.5 mL) may suggest ejaculatory duct obstruction or congenital bilateral absence of vas deferens, as indicated by the American Urological Association 2

Additional Testing

Post-ejaculatory urinalysis is indicated when ejaculate volume is <1 mL (except in patients with bilateral vasal agenesis or hypogonadism) to diagnose retrograde ejaculation, as recommended by the American Academy of Family Physicians 2, 4
Transrectal ultrasonography (TRUS) is indicated in azoospermic patients with palpable vasa and low ejaculate volumes to evaluate for ejaculatory duct obstruction, according to the American Institute of Ultrasound in Medicine 2
Scrotal ultrasonography is indicated when physical examination of the scrotum is difficult or inadequate, or when a testicular mass is suspected, as recommended by the European Association of Urology 2, 3

Genetic Testing

Karyotype testing is recommended for patients with azoospermia or severe oligospermia (<5 million/mL), and Y-chromosome microdeletion analysis is mandatory for those with azoospermia or sperm concentration <1 million/mL, as recommended by the European Society of Human Genetics 3, 4
Cystic fibrosis transmembrane conductance regulator (CFTR) gene testing should be offered to female partners of men with congenital bilateral absence of vas deferens, according to the American College of Medical Genetics 2

Important Considerations

FSH levels alone cannot definitively predict sperm retrieval success in all cases, as men with maturation arrest on histology can have normal FSH despite severe spermatogenic dysfunction, as indicated by the European Association of Urology 3, 5
Genetic abnormalities are more common in men with severe spermatogenic dysfunction, with potential implications for offspring, according to the American Society for Reproductive Medicine 4
Before proceeding with intracytoplasmic sperm injection (ICSI), patients should be informed about potential genetic abnormalities associated with azoospermia, as recommended by the American Society for Reproductive Medicine 2, 4
Testosterone replacement therapy should be avoided in men desiring fertility as it can suppress spermatogenesis, according to the American Urological Association 4, 5

Evaluation of Azoospermia

Initial Confirmation and Assessment

When a semen analysis shows azoospermia, the laboratory should centrifuge the ejaculate and examine the pellet under microscopy for rare sperm, as sperm pellet analysis can identify motile or non-motile sperm in approximately 18-23% of men initially diagnosed with azoospermia 6

Physical Examination

Assess testicular size and consistency: normal-sized testes suggest obstructive azoospermia while atrophic testes indicate non-obstructive azoospermia 6

Hormonal Evaluation

Measure serum testosterone and follicle-stimulating hormone (FSH) levels as the primary hormonal assessment, as FSH levels >7.6 IU/L typically suggest non-obstructive azoospermia (spermatogenic failure), while normal FSH levels suggest obstructive azoospermia 6

Distinguishing Obstructive vs. Non-obstructive Azoospermia

Obstructive azoospermia is characterized by normal-sized testes, normal FSH levels (<7.6 IU/L), dilated and/or indurated epididymides, and possible absence of vas deferens 6
Non-obstructive azoospermia is characterized by atrophic testes, elevated FSH (>7.6 IU/L), and normal epididymides and vas deferens 6

Genetic Testing

Karyotype testing is recommended for all patients with azoospermia or severe oligospermia (<5 million/mL) 6

Testicular Appearance in Azoospermia Due to Total Dysfunction

Distinguishing Obstructive vs. Non-obstructive Azoospermia

Non-obstructive azoospermia (testicular dysfunction) is characterized by atrophic testes, while obstructive azoospermia typically presents with normal-sized testes 7
In obstructive azoospermia, the physical examination typically reveals testes of normal size that are fully descended into the scrotum, often with dilated and/or indurated epididymides 7

Testicular Atrophy in Non-obstructive Azoospermia

According to the European Association of Urology guidelines, men with non-obstructive azoospermia due to testicular dysfunction typically have atrophic testes 8

Clinical Implications

Scrotal ultrasonography is indicated when physical examination of the scrotum is difficult or inadequate, or when testicular abnormalities are suspected 9
Genetic testing, including karyotype analysis and Y-chromosome microdeletion testing, is essential for diagnosing the underlying cause of non-obstructive azoospermia 8
The presence of normal-sized testes with good vascularity in a patient with confirmed azoospermia should prompt consideration of obstructive causes rather than primary testicular dysfunction 7

Relationship Between Atrophied Testicles and Blood Flow

Pathophysiology of Testicular Atrophy and Blood Flow

Testicular atrophy is characterized by decreased testicular volume and is commonly associated with reduced blood flow as demonstrated by color Doppler ultrasonography 10, 11

Diagnostic Assessment of Blood Flow in Atrophied Testes

Color Doppler and power Doppler ultrasonography are the primary methods for evaluating testicular blood flow, with power Doppler being more sensitive for detecting low-flow states 10, 12
Spectral Doppler analysis allows quantitative assessment of testicular perfusion by measuring arterial velocity and resistive index 10, 13
When examining atrophied testes, blood flow should be compared to the contralateral normal testis as an internal control 12, 13
Specific abnormal flow patterns in atrophied testes include decreased arterial velocity 10, 13, increased resistive index 10, 11, monophasic waveforms 10, 12, and reduced or absent diastolic flow 10, 13

Clinical Implications

Testicular atrophy with reduced blood flow is commonly associated with non-obstructive azoospermia and infertility 14, 15, 16
In men with testicular atrophy, especially with FSH greater than 7.6 IU/L, spermatogenic failure (non-obstructive azoospermia) is the likely cause 14, 15

Important Considerations

Not all atrophied testes have completely absent blood flow - the reduction is often relative rather than absolute 10, 11

Scrotal Ultrasound Findings in Non-Obstructive Azoospermia

Primary Testicular Findings

Non-homogeneous testicular architecture is commonly observed, representing signs of testicular dysgenesis and impaired spermatogenesis, in men with non-obstructive azoospermia 17, 18, 19
Testicular microcalcifications may be present, which are associated with an 18-fold higher prevalence of testicular cancer in infertile men 17, 18, 19

Clinical Utility and Diagnostic Value

The European Association of Urology guidelines specify that scrotal ultrasound has a relevant role in non-obstructive azoospermia evaluation for testicular volume assessment, detection of testicular tumors, and assessment of testicular anatomy and structure 17, 18, 19
Scrotal ultrasound can effectively distinguish non-obstructive azoospermia from obstructive azoospermia based on testicular volume, epididymal architecture, and vascularity 17, 18, 19

Important Caveats

While ultrasound can suggest non-obstructive azoospermia based on testicular volume and architecture, FSH levels do not accurately predict the presence of spermatogenesis in all cases, as men with maturation arrest can have normal FSH and testicular volume 17
Routine ultrasound screening for all infertile men may result in over-diagnosis of incidental testicular masses 17, 18, 19

Management of Obstructive Azoospermia in Cystic Fibrosis (CBAVD)

Diagnostic Criteria

Men with cystic fibrosis‑related congenital bilateral absence of the vas deferens (CBAVD) present with low ejaculatory volume (< 1.5 mL), absent palpable vas deferens bilaterally, and acidic seminal pH. 20

Imaging Recommendations

Transrectal ultrasound does not aid in the diagnosis or treatment of CBAVD and should be omitted from the work‑up. 20
Renal ultrasonography is mandatory for every patient with unilateral or bilateral vas deferens agenesis because 26–75 % of those with unilateral absence and 10 % of those with bilateral absence have ipsilateral renal anomalies, including renal agenesis. 20
When epididymal congestion is identified on examination, sperm cryopreservation from a testicular biopsy should be attempted if testicular sperm extraction is being considered. 20

Genetic Evaluation

Comprehensive CFTR mutation analysis must be offered to all men with CBAVD and to their female partners before proceeding with assisted reproductive technologies. 21
Genetic counseling is required before conception because pathogenic CFTR mutations can be transmitted to offspring. 21
The same recommendation for CFTR testing is reiterated in a second 2017 review, emphasizing the need for thorough genotyping beyond the common 31‑mutation panel. 22

Reproductive Treatment Strategy

The standard approach for obstructive azoospermia due to CBAVD is micro‑dissection epididymal sperm aspiration (MESA) combined with intracytoplasmic sperm injection (ICSI). (Guideline‑based practice; no specific citation in the source text.)
Microsurgical reconstruction of the vas deferens is not feasible in CBAVD, distinguishing it from other causes of obstructive azoospermia where reconstruction may restore natural fertility. (Guideline‑based practice; no specific citation in the source text.)

Pre‑Treatment Clinical Considerations

Exogenous testosterone should never be prescribed to men desiring fertility, as it suppresses endogenous spermatogenesis via negative feedback on FSH and LH, potentially causing prolonged azoospermia. (Guideline‑based practice; no specific citation in the source text.)
Patients must receive counseling regarding the potential genetic implications of using assisted reproduction, including the risk of transmitting CFTR mutations to male offspring. (Guideline‑based practice; no specific citation in the source text.)