What tests are done for hair loss evaluation?

When you notice more hair shedding than usual or thinning in patches, a step-by-step evaluation helps pinpoint the cause and guide treatment. "Hair loss tests" fall into three main categories: non-invasive scalp and hair assessments, laboratory tests and, in some cases, a scalp biopsy. Below is an overview of the most commonly used tests and when they're indicated.

1. Initial Clinical Evaluation
   Before ordering any tests, your doctor will take a thorough history and do a physical exam. Key points include:

• Pattern of hair loss (diffuse thinning vs. patchy bald spots)
• Duration and speed of shedding
• Recent illnesses, surgeries or high-stress events
• Diet, weight changes or strict dieting
• Medications and supplements
• Family history of hair loss or autoimmune disease
• Signs of scalp inflammation (redness, scaling, pustules)

2. Non-Invasive Scalp and Hair Tests
   These quick, in-office procedures help determine the type of hair loss and whether further testing is needed.

• Pull Test
– Gently tug on a small bundle of about 40–60 hairs.
– Normally, 2–3 hairs come out; more suggests active shedding (telogen effluvium or active alopecia).

• Tug Test
– Hold hair firmly at both ends and stretch.
– Breakage in the shaft may indicate structural hair disorders (e.g., trichorrhexis nodosa).

• Hair Washing ("Wash") Test
– Collect hairs shed during a standardized wash routine.
– Counting shed hairs over three washes quantifies shedding.

• Trichoscopy (Dermatoscopy of the Scalp)
– A handheld device with ×10–×70 magnification examines follicle openings, hair shaft diameter and scalp surface.
– Can differentiate androgenetic alopecia (hair diameter diversity, miniaturization) from alopecia areata (exclamation-mark hairs, yellow dots) and scarring alopecias.
– This non-invasive tool often eliminates the need for an immediate biopsy.

• Phototrichogram and Videotrichogram
– High-resolution photos track hair growth over days to weeks.
– Measures hair density, growth rate and anagen (growth) to telogen (resting) ratios.

3. Laboratory Tests
   Blood tests are guided by clinical suspicion. Routine screening for most men and women with typical pattern hair loss (androgenetic alopecia) may not be necessary. But when diffuse shedding, systemic symptoms or rapid progression are present, consider:

• Complete Blood Count (CBC)
– Detects anemia or other blood disorders that can contribute to hair shedding.

• Iron Studies
– Ferritin, serum iron and total iron-binding capacity.
– Low iron stores (ferritin < 30–50 ng/mL) are linked to telogen effluvium.

• Thyroid Function Tests
– Thyroid-stimulating hormone (TSH) and free T4.
– Both hypothyroidism and hyperthyroidism can cause diffuse hair thinning.

• Hormone Panel (especially in women with signs of hyperandrogenism or menstrual irregularities)
– Total and free testosterone
– Dehydroepiandrosterone-sulfate (DHEA-S)
– Androstenedione
– Luteinizing hormone (LH) and follicle-stimulating hormone (FSH)
– Prolactin

• Vitamin D, Vitamin B12 and Zinc
– Deficiencies have been implicated in chronic telogen effluvium and other hair disorders.

• Autoimmune Markers (if alopecia areata or autoimmune thyroid disease is suspected)
– Antinuclear antibody (ANA)
– Anti–thyroid peroxidase (TPO) and anti–thyroglobulin antibodies

• Scalp Culture or KOH Prep
– If fungal infection (tinea capitis) is suspected, a scraping or culture can identify dermatophytes.

4. Scalp Biopsy
   Reserved for cases where non-invasive tests are inconclusive or when scarring alopecia is suspected. A small punch (4 mm) of scalp skin is removed under local anesthesia and examined under a microscope. Two types of sections may be prepared:

• Vertical section
– Shows the entire length of hair follicles; useful for assessing inflammation in the epidermis and follicle.
• Horizontal section
– Highlights follicle number and cycling; ideal for determining the ratio of vellus to terminal hairs.

Findings guide diagnosis of lichen planopilaris, frontal fibrosing alopecia, discoid lupus or other cicatricial (scarring) conditions.

5. Specialized Tests
   In select scenarios, additional tests may be helpful:

• Hormone-stimulating Tests (e.g., ACTH stimulation)
– If adrenal causes of hair loss (Cushing's syndrome) are considered.

• Genetic Testing
– Emerging role in androgenetic alopecia research but not yet routine.

• Transient Elastography (FibroScan)
– Primarily used for liver fibrosis assessment in chronic liver disease (not directly for hair loss). However, since severe systemic illnesses like cirrhosis can impact hair health, your doctor may coordinate care with a hepatologist if liver disease is suspected.

If you're experiencing patchy hair loss and want to understand whether your symptoms align with Alopecia Areata, a free AI-powered symptom checker can help you quickly assess your condition and decide whether to schedule an appointment with a dermatologist.

6. Putting It All Together
   Your dermatologist or primary doctor will integrate:

• Clinical history and pattern of hair loss
• Findings from pull tests and trichoscopy
• Laboratory results
• Biopsy (if needed)

This comprehensive approach helps distinguish:

• Androgenetic alopecia (male/female pattern)
• Telogen effluvium (diffuse shedding after a trigger)
• Alopecia areata (autoimmune, patchy)
• Scarring alopecias (irreversible if untreated early)
• Nutritional or systemic causes

Remember: early diagnosis often leads to more effective treatment.

Speak to a doctor if you experience:

• Rapid or widespread hair loss
• Scalp pain, burning or severe itching
• Signs of infection (redness, swelling, fever)
• Any other symptoms that are life-threatening or concerning

Your healthcare provider can select the right mix of "hair loss tests" for your situation, from simple pull tests and blood work to advanced trichoscopy and scalp biopsy. Prompt evaluation is the first step toward regaining healthy hair.