dromlakhani Obtain endocrine laboratory evaluation
STEP 1 — Gather Information
Collect menstrual history (amenorrhea ≥3 months or cycle >45 days), assess for pregnancy, and evaluate for clinical hyperandrogenism (hirsutism, acne, virilization) or signs suggestive of late-onset congenital adrenal hyperplasia (precocious puberty, hypertension, electrolyte abnormalities).
STEP 2 — Rule In / Rule Out
Rule out pregnancy via urine or serum hCG; if positive, manage pregnancy and do not proceed with this endocrine panel. If negative, continue to next step.
STEP 3 — Classify or Stratify
Determine whether to add targeted assays: if clinical hyperandrogenism is present, add total testosterone and DHEA-S; if late-onset CAH is suspected, add 8 AM 17-hydroxyprogesterone.
STEP 4 — Decide
Order the base panel (TSH, free T4, prolactin, LH, FSH, estradiol, AMH) plus any indicated additional tests based on stratification; draw blood preferably in the early follicular phase if timing is known, but results are interpretable regardless of cycle day for most assays.
Clinical Guardrails / Mimics / Pitfalls
Do not order these labs without first excluding pregnancy; avoid interpreting a single estradiol value as diagnostic of FHA; do not rely on LH/FSH ratio alone to differentiate FHA from PCOS; do not obtain 17-OHP without clinical suspicion for CAH; do not order testosterone/DHEA-S in the absence of hyperandrogenism signs.
Clinical Example
A 24-year-old runner presents with 5 months of amenorrhea, BMI 17.2, and no hirsutism. Pregnancy test is negative. She denies virilization or CAH symptoms. Order TSH, free T4, prolactin, LH, FSH, estradiol, and AMH. No testosterone/DHEA-S or 17-OHP added.
Source: Functional Hypothalamic Amenorrhea: An Endocrine Society Clinical Practice Guideline, Endocrine Society, 2017, DOI:10.1210/jc.2017-00131