From the Guidelines
Laboratory tests recommended for women experiencing hair loss typically include a complete blood count (CBC), thyroid function tests (TSH, free T3, free T4), iron studies (ferritin, iron, total iron binding capacity), vitamin D levels, and hormone panels including testosterone, DHEAS, and androstenedione, as supported by recent guidelines 1. These tests help identify common underlying causes of female hair loss such as iron deficiency, thyroid disorders, and hormonal imbalances.
- Additional tests may include:
- Zinc levels
- Comprehensive metabolic panel
- Antinuclear antibody test for autoimmune conditions
- PCOS screening if symptoms warrant, with the use of TT, FT, and FAI as first-line laboratory tests to assess biochemical hyperandrogenism in the diagnosis of PCOS 1
- A scalp biopsy might be recommended in cases where the diagnosis remains unclear after initial testing, and can help examine the hair follicles under a microscope, with the option of immunohistology 1. These laboratory evaluations are crucial because many causes of female hair loss are treatable once identified.
- For example, iron supplementation can reverse hair loss caused by iron deficiency, while thyroid medication can address hair thinning related to thyroid dysfunction, and hormone panels can help identify hormonal imbalances that may be contributing to hair loss 1. Testing should be tailored to the individual's clinical presentation, age, and medical history, with follow-up testing as needed based on initial results.
- It is also important to rule out differential diagnoses, such as female-pattern hair loss, alopecia areata, or inflammatory (scarring) alopecia, through laboratory testing and examination 1.
From the Research
Laboratory Tests for Hair Loss in Women
The following laboratory tests are recommended for women experiencing hair loss:
- Complete blood count (CBC) to rule out iron deficiency anemia 2, 3, 4
- Serum ferritin concentration to confirm iron deficiency 2, 3, 5, 4
- Thyroid function tests (T3, T4, and TSH) to check for thyroid hormone disorders 3, 4
- Vitamin D 25OH to check for vitamin D deficiency 4
- Hair pull, hair tug, Hair Card, and hair mount to evaluate hair and scalp 4
- Scalp biopsy to confirm a diagnosis, especially in cases of cicatricial alopecia 4
Specific Tests for Female Pattern Hair Loss
For women with female pattern hair loss (FPHL), the following tests may be ordered:
- Hormone tests, including sex hormones, adrenal and thyroid hormones 6
- Iron metabolism tests to check for iron deficiency 6
- Insulin levels to check for insulin resistance 6
- Tests for androgenization, such as menstrual disorders, hirsutism, and acne 6
Importance of Iron Deficiency Testing
Iron deficiency is a common cause of hair loss in women, and testing for iron deficiency is essential 2, 3, 5. A study found that 25% of women with alopecia had iron deficiency, and treating iron deficiency can improve hair loss 5. Another study found that automatic registration and measurement of ferritin can detect iron deficiency in 27.9% of women with alopecia 5.