What are the indications for hormone labs in females?

Indications for Hormone Labs in Females

Hormone testing in females should be reserved for specific clinical indications of hormonal dysfunction—not performed as routine screening—and should target menstrual irregularities, signs of androgen excess, delayed puberty, or suspected premature ovarian insufficiency. 1

Prepubertal and Adolescent Indications

Delayed Puberty

• Measure FSH and estradiol if no signs of puberty by age 13 years, as this represents the critical threshold for evaluation 1
• Prepubertal females age ≥11 years with delayed puberty require laboratory evaluation 1
• Look for early-onset body odor, axillary or pubic hair, accelerated growth, advanced bone age, and genital maturation—these warrant hormonal testing even before age 13 2, 1

Primary Amenorrhea

• Evaluate with hormone testing if no menses by age 16 years in the presence of other evidence of puberty 1

Adult Female Indications

Menstrual Dysfunction

• Secondary amenorrhea (absence of menses for ≥4 months) requires hormone testing 1
• Oligomenorrhea (irregular cycles or cycle length >35 days) warrants evaluation 1
• These represent the most common indications for hormone testing in reproductive-age women 1

Signs of Androgen Excess

• Test when postpubertal females present with infrequent menses, hirsutism, androgenetic alopecia, infertility, polycystic ovaries, clitoromegaly, or truncal obesity 2
• Routine endocrinologic evaluation is NOT recommended for acne alone unless additional signs of androgen excess are present 2
• Recalcitrant acne with hyperandrogenism features should prompt testing 2

Suspected Premature Ovarian Insufficiency (POI)

• Women with clinical symptoms of POI, such as irregular menstrual cycles, require FSH and estradiol measurement 2, 1
• Cancer survivors treated with alkylating agents and/or radiotherapy potentially exposing the ovaries need hormone surveillance 2, 1

Recommended Hormone Panel

Standard Tests

• FSH and estradiol should be measured during the early follicular phase (days 2-5) in women with oligomenorrhea 1, 3
• For amenorrhea, FSH and estradiol can be measured randomly 1
• LH is useful for evaluating the hypothalamic-pituitary-gonadal axis 1
• TSH and free T4 should be measured to rule out thyroid dysfunction, as this is a common differential diagnosis 1

Comprehensive Androgen Evaluation (When Indicated)

• Free and total testosterone, DHEA-S, androstenedione, LH, and FSH comprise a typical screening panel for suspected hyperandrogenism 2
• Total testosterone is the best single hormonal marker for PCOS, with abnormal values in 70% of cases 4
• Testosterone, androstenedione, or LH (alone or in combination) are elevated in 86% of women with PCOS 4

Critical Timing Considerations

Menstrual Cycle Timing

• Schedule blood tests on day 2,3,4, or 5 of the menstrual cycle for accurate baseline assessment 3
• Testing should be performed during the early follicular phase when hormonal levels are at baseline 3
• Baseline FSH and LH measurements should ideally be the average of three estimations taken 20 minutes apart for maximum accuracy 3

Special Circumstances

• Women on hormonal contraceptives should stop them at least 2 months before testing if assessing baseline reproductive function 3
• Hormone markers vary throughout the menstrual cycle and are affected by hormonal contraceptive therapy and sex steroid replacement therapy 2
• For women with irregular or absent periods, contact the provider for specific timing instructions 3

Common Pitfalls to Avoid

Inappropriate Testing

• Do NOT perform routine endocrinologic evaluation for the majority of acne patients—only test those with additional signs of androgen excess 2
• Abandon using LH/FSH ratio as a primary diagnostic criterion for PCOS due to its low sensitivity (only abnormal in 41-44% of cases) 4
• Routine microbiologic or endocrinologic testing without specific symptoms is not recommended 1

Interpretation Errors

• Interpretation must consider the patient's age, as normal ranges vary throughout the lifespan 1
• Fluctuations in hormone levels, particularly AMH, may occur throughout the menstrual cycle, especially in women under 25 years 1
• Absolute gonadotrophin values can differ significantly between assay methods, even when using the same reference preparation 4

When to Refer to Specialists

Endocrinology/Gynecology Referral

• Refer prepubertal females with no signs of puberty by age 13 years and elevated FSH levels 1
• Refer postpubertal females with menstrual dysfunction suggestive of POI 1
• Consider referral for all patients diagnosed with POI for hormone replacement therapy consideration 1

Complex Cases

• Growth charts and hand films for bone age are good screening tools before specific hormonal testing in prepubertal children 2
• Differential diagnosis of PCOS includes thyroid disease, prolactin excess, and nonclassical congenital adrenal hyperplasia—complex cases warrant specialist evaluation 2