What laboratory tests are recommended for premenopausal women (females who have not yet reached menopause)?

Laboratory Testing for Premenopausal Women

The specific laboratory tests recommended for premenopausal women depend entirely on the clinical context, but routine screening should include coeliac serology for iron deficiency anaemia, thyroid function tests when evaluating menstrual irregularities or suspected hypogonadism, and cancer screening per age-appropriate guidelines.

Context-Specific Laboratory Evaluation

For Iron Deficiency Anaemia (IDA)

When IDA is identified in premenopausal women, the following laboratory approach is recommended:

• Coeliac disease screening with tissue transglutaminase antibodies (tTG Ab) is mandatory, as coeliac disease is present in up to 4% of premenopausal women with IDA 1
• Complete blood count to confirm low hemoglobin, microcytosis, and hypochromia 1
• Serum ferritin to document iron deficiency 1
• No routine gastrointestinal investigation is needed for women under age 50 unless specific red flags are present (upper GI symptoms, strong family history of colorectal cancer, or persistent IDA despite iron replacement) 1

For Menstrual Irregularities or Suspected Hypogonadism

When evaluating premenopausal women with menstrual irregularities, mood changes, or other evidence of hormonal dysfunction:

• Serum estradiol with LH/FSH should be assessed to identify hypogonadism, where low estradiol levels are accompanied by abnormal gonadotropin levels 1
• Thyroid function tests (TSH, free T4) are essential before initiating treatment for premenstrual mood changes, as hypothyroidism can mimic premenstrual symptoms with mood changes and fatigue 2, 3
• Consider prolactin levels if the diagnosis is unclear, to help identify underlying hormonal imbalances 2

Important caveat: FSH levels are unreliable in women with prior chemotherapy or pelvic radiation and should not be used for hormonal assessment in these populations 2.

For Premenstrual Mood Symptoms

When evaluating premenopausal women specifically for premenstrual syndrome (PMS) or premenstrual dysphoric disorder (PMDD):

• Thyroid function testing to exclude hypothyroidism as an alternative cause 2
• Diabetes screening to rule out metabolic causes of mood and energy changes 2
• Consider estradiol, FSH, LH, and prolactin if the diagnosis remains unclear after initial evaluation 2

For Osteoporosis Risk in Chronic Liver Disease

In premenopausal women with chronic liver disease being evaluated for osteoporosis:

• Thyroid function tests 1
• Bone function tests including corrected serum calcium and serum phosphate 1
• Serum estradiol and LH/FSH if there is menstrual irregularity or other evidence of hypogonadism 1
• 25-OH vitamin D levels in high-risk patients (housebound, malabsorption, chronic cholestasis) or if hypocalcemic 1

For Immune Checkpoint Inhibitor Therapy

Premenopausal women receiving immune checkpoint inhibitors require specific endocrine monitoring:

• LH, FSH, and estrogen levels should be evaluated in those with fatigue, loss of libido, mood changes, or oligomenorrhea 1
• ACTH and morning cortisol to assess for adrenal insufficiency 1
• TSH and free T4 for thyroid function 1
• Electrolytes to screen for endocrine complications 1

Routine Cancer Screening

Age-appropriate cancer screening for premenopausal women includes:

• Cervical cancer screening with Pap test starting at age 21, performed annually with conventional Pap or every 2 years with liquid-based Pap 1
• Clinical breast examination every 3 years for women in their 20s and 30s, then annually starting at age 40 1
• Annual mammography starting at age 40 1
• Colorectal cancer screening starting at age 50 with annual FOBT/FIT or colonoscopy every 10 years 1

Preconception Laboratory Testing

For premenopausal women planning pregnancy, recommended laboratory evaluation includes:

• Complete blood count to screen for anemia 1
• Blood type and screen 1
• Rubella, syphilis, hepatitis B, and HIV screening when indicated 1
• Gonorrhea and chlamydia screening when indicated 1
• Diabetes screening when indicated 1
• Consider thyroid-stimulating hormone levels 1
• Cervical cytology if due 1

Common Pitfalls to Avoid

• Do not rely on FSH levels alone in women with prior chemotherapy or pelvic radiation, as these are unreliable in this population 2
• Always check thyroid function before attributing mood symptoms solely to premenstrual syndrome, as hypothyroidism commonly presents with similar symptoms 2, 3
• Do not perform routine gastrointestinal endoscopy in young premenopausal women with IDA unless age ≥50, non-menstruating status, red flag symptoms, or strong family history of GI malignancy is present 1
• Recognize that morning cortisol is unreliable in patients on corticosteroids for other conditions, as this causes iatrogenic secondary adrenal insufficiency 1