Laboratory Workup for Hair Loss in a 65-Year-Old Female
Order a complete blood count, serum ferritin, thyroid stimulating hormone (TSH), and vitamin D 25-OH levels as your initial laboratory panel for this patient. 1
Core Laboratory Tests
The following tests should be obtained in all patients presenting with hair loss:
Complete blood count (CBC): Evaluates for anemia, which commonly contributes to hair loss in women. Hemoglobin levels should ideally be greater than 13.0 g/dL for optimal hair growth. 1, 2
Serum ferritin: This is critical as iron stores significantly impact hair growth potential. Target ferritin levels of 70 ng/mL or greater for optimal hair growth, not just the lower limit of normal laboratory ranges. 1, 2
Thyroid stimulating hormone (TSH): Screens for thyroid dysfunction, a common reversible cause of diffuse hair loss in women. 1, 3
Vitamin D 25-OH: Vitamin D deficiency has been associated with hair loss and should be assessed in all patients. 1
Additional Considerations Based on Clinical Context
While the above four tests represent the standard initial workup, additional testing may be warranted based on specific clinical findings:
Serum folate and vitamin B12: Consider if nutritional deficiency is suspected or if the patient has risk factors for malabsorption. Optimal B12 levels are between 300-1000 ng/L for hair growth. 2
Hormonal evaluation: In a 65-year-old postmenopausal woman, routine androgen testing is generally not necessary unless there are signs of hyperandrogenism (hirsutism, virilization). Female pattern hair loss is highly prevalent in this age group (52% in postmenopausal women) and is primarily age-related rather than hormone-driven. 4
Important Caveats
Routine autoimmune screening is not recommended unless there are specific clinical features suggesting autoimmune disease. Even in alopecia areata, which has autoimmune associations, the increased frequency of other autoimmune diseases is insufficient to justify routine screening. 5
The diagnosis of hair loss patterns is primarily clinical, based on history and physical examination including hair pull tests and scalp evaluation. Laboratory tests serve to identify treatable contributing factors rather than establish the primary diagnosis. 1, 6, 3