What laboratory tests should be rechecked regularly for a female patient on Androgel (testosterone) therapy?

Laboratory Monitoring for Women on Androgel (Testosterone Gel)

Women on testosterone therapy with Androgel require monitoring of serum testosterone levels at 2-3 months after initiation or dose adjustment, then every 6-12 months once stable, along with periodic assessment of hematocrit, hemoglobin, and liver function tests. 1, 2

Initial Pre-Treatment Laboratory Assessment

Before initiating Androgel in women, baseline laboratory values should be documented:

• Morning total testosterone levels measured on at least two separate occasions to confirm hypogonadism, though normative data for women across the lifespan remain inadequately defined 2, 3
• Free testosterone by equilibrium dialysis in addition to total testosterone, particularly when total testosterone is borderline 1
• Baseline hematocrit or hemoglobin to monitor for potential erythrocytosis during treatment 1, 2
• Liver function tests as a baseline for comparison during ongoing therapy 2

Ongoing Monitoring During Treatment

Testosterone Level Monitoring

• Measure testosterone levels at 2-3 months after treatment initiation or any dose adjustment to ensure adequate therapeutic levels 1, 2
• Once stable levels are confirmed on a given dose, monitor every 6-12 months 1
• For women on testosterone gel, testosterone levels can be measured at any time after 2-3 months of stable therapy, as transdermal preparations provide relatively stable day-to-day levels 1
• Target mid-normal testosterone levels appropriate for the patient's affirmed gender identity 4

Hematologic Monitoring

• Monitor hematocrit and hemoglobin periodically throughout treatment 2, 5
• Withhold treatment if hematocrit exceeds 54% and consider phlebotomy in high-risk cases 1
• Erythrocytosis is a known risk of testosterone therapy, with injectable forms carrying higher risk than transdermal preparations 1
• Hemoglobin typically increases during testosterone therapy, with correction of anemia observed in some patients 5, 6

Hepatic Monitoring

• Monitor liver function tests periodically during ongoing testosterone therapy 2
• Testosterone replacement therapy may be associated with transient elevations in liver enzymes that are usually self-limited 4

Laboratory Value Interpretation in Transgender Patients

For transgender men (female-to-male) on testosterone therapy:

• After more than 1 year of testosterone therapy, interpret laboratory values based on male reference ranges 4
• For those newly initiated on testosterone (less than 1 year), laboratory values may be transitional and should be interpreted with caution, understanding that values will shift over time 4
• Creatinine reference ranges should be interpreted based on affirmed gender after 1 year of therapy, as testosterone increases lean body mass by approximately 4 kg 4
• Electrolyte monitoring is important, particularly if spironolactone was previously used, as sodium, potassium, and blood urea nitrogen may fluctuate 4

Additional Monitoring Considerations

Estradiol Monitoring

• Routine estradiol monitoring is NOT recommended in asymptomatic patients on testosterone therapy 7
• Check estradiol levels only if patients develop new breast symptoms, including breast pain, tenderness, or nipple discomfort 7
• Estradiol levels commonly increase during testosterone therapy due to peripheral aromatization, but symptomatic gynecomastia is uncommon despite rising estradiol 7

Lipid Monitoring

• Monitor lipid concentrations periodically, as testosterone therapy may improve lipid profiles, including reductions in triglycerides and improvements in HDL cholesterol 1, 2

Metabolic Monitoring

• Assess fasting plasma glucose and insulin resistance markers, as testosterone therapy can improve glycemic control and metabolic parameters 1

Critical Pitfalls to Avoid

• Do not skip baseline laboratory assessment before initiating therapy, as this prevents proper monitoring for adverse effects 1, 2
• Do not ignore mild erythrocytosis (hematocrit 50-52%), particularly in patients with cardiovascular risk factors, as even modest elevations increase blood viscosity and thrombotic risk 1
• Do not continue full-dose testosterone when hematocrit exceeds 54%, as this is an absolute indication to withhold therapy 1
• Do not measure testosterone levels at inappropriate times relative to application, as this may lead to inaccurate dose adjustments 1
• Do not assume laboratory reference ranges without considering duration of testosterone therapy and affirmed gender in transgender patients 4

Special Considerations for Female-to-Male Transgender Patients

• Screen for liver abnormalities and polycythemia before initiating high-dose androgen therapy in female-to-male transgender patients 4
• Duration of testosterone therapy, dose, and route of administration should be recorded when interpreting laboratory values 4
• For patients who have stopped testosterone therapy, laboratory values typically reflect their sex assigned at birth within 3 months of discontinuation 4