Laboratory Evaluation for Hot Flashes
For patients experiencing hot flashes, obtain FSH, estradiol, thyroid-stimulating hormone (TSH), and complete blood count to confirm menopausal status and rule out secondary causes. 1
Essential Laboratory Tests
The initial workup should include:
- FSH and estradiol levels to confirm menopausal status, particularly important in women with premature or early-onset symptoms 1
- TSH to exclude thyroid disease, which is a critical secondary cause that must be ruled out in any patient with vasomotor symptoms 2, 1
- Complete blood count to assess for anemia and other hematologic abnormalities 1
- Glucose testing should be considered to exclude diabetes as a secondary cause 2
Clinical Context Matters
The laboratory approach differs based on patient characteristics:
In women with known breast cancer history, particularly those on tamoxifen, hot flashes may actually indicate drug effectiveness rather than pathology 1. However, the same laboratory evaluation is still warranted to exclude other causes.
In women with premature menopause or chemotherapy-induced menopause, more comprehensive hormonal evaluation may be necessary beyond the basic panel 1
Interpreting Results and Next Steps
Once laboratory confirmation of menopause is established without other pathology:
First-line non-hormonal options include SNRIs (venlafaxine 37.5-75 mg daily), SSRIs, or gabapentin 900 mg daily 1, 3
Critical drug interaction warning: In women taking tamoxifen, avoid paroxetine and fluoxetine as they inhibit CYP2D6 and reduce conversion of tamoxifen to its active metabolite (endoxifen) 1, 3. Prefer citalopram or venlafaxine in this population 1
Common Pitfalls to Avoid
Do not dismiss hot flashes as "normal for age" without proper evaluation, as they significantly impact quality of life and warrant treatment 2
Do not overlook drug interactions, especially the tamoxifen-SSRI interaction which can compromise cancer treatment efficacy 1, 3
Do not assume all hot flashes are menopausal - secondary causes including thyroid disease, diabetes, carcinoid syndrome, pheochromocytoma, and other systemic conditions must be excluded 2, 4