Doctors use various blood tests for hair loss to identify the cause, including tests for hormone levels, thyroid function, and nutrient deficiencies like iron and vitamin D.
Diagnosing hair loss involves understanding its cause, which can vary from person to person. Doctors often start by asking about your health history and examining your scalp.
Sometimes, doctors order blood tests for hair loss to check for underlying problems like hormone imbalances or nutrient deficiencies that may affect hair growth.
This article covers the different types of blood tests used to diagnose hair loss.
What blood tests diagnose hair loss?
Doctors sometimes use blood tests to determine the underlying cause of hair loss. Common blood tests for hair loss includeTrusted Source:
Complete blood count (CBC)
A complete blood count (CBC) test measures different components of your blood, including red and white blood cells, hemoglobin, and platelets.
This test helps diagnose conditions like anemia, which, when caused by iron deficiency, can lead to hair loss due to insufficient iron required for hair follicle growth and maintenance.
Vitamin level test for hair loss
Vitamin deficiencies, especially in vitamin D and B12, can lead to hair loss. A 2023 pilot studyTrusted Source linked vitamin D deficiency to alopecia areata, a condition where the immune system destroys hair follicles, leading to hair loss.
Iron and ferritin studies
Iron helps produce hemoglobin, which carries oxygen to hair follicles to support healthy growth. Low iron levels can slow hair growth and lead to thinning.
Ferritin is a protein that stores iron in the body. Low ferritin levels suggest depleted iron reserves, which can weaken hair and cause shedding.
Iron and ferritin studies can help doctors diagnose conditions like telogen effluvium, a hair loss condition that can result from iron deficiency.
Blood sugar (glucose) levels
Glucose tests help doctors detect blood sugar imbalances linked to diabetes. A 2019 study found a strong link between uncontrolled blood sugar levels in type 2 diabetes and severe central scalp hair loss, particularly in African American women.
Thyroid-stimulating hormone (TSH)
Research suggests that both hypothyroidism (underactive thyroid) and hyperthyroidism (overactive thyroid) can lead to hair thinning or loss.
A TSH test helps evaluate thyroid function and determines if thyroid problems contribute to hair loss.
Sex hormone tests for hair loss
Hormonal imbalances involving testosterone, estrogen, or dihydrotestosterone (DHT), are a common cause of hair loss, especially male pattern baldness (androgenic alopecia).
Tests for sex hormones help doctors diagnose male pattern baldness and hormone-related conditions like polycystic ovary syndrome (PCOS).
Antinuclear antibody test (ANA)
An antinuclear antibody (ANA) test helps identifyTrusted Source autoimmune disorders like lupus, which can damage the scalp and lead to scarring hair loss.
ANA testing helps doctors identify certain types of hair loss, especially if an autoimmune condition might be causing it.
Inflammatory markers
Chronic inflammation can interfere with the hair growth cycle, leading to conditions like telogen effluvium and alopecia areata.
Tests like erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels detect inflammation in the body.
Venereal disease test
Syphilis, a sexually transmitted infection (STIs), can cause hair loss. This often appears as patchy bald spots known as “moth-eaten alopecia.” A venereal disease test is specific for identifying infections like syphilis.
Cortisol levels test
Chronic stress can causeTrusted Source hair loss conditions like telogen effluvium, in which hair falls out more than usual because the hair follicles enter into a resting phase and stop growing prematurely.
A cortisol test measures the levels of the stress hormone cortisol in your blood.
In addition to blood tests, doctors may use other tests to diagnose hair loss, including:
- Scalp biopsy: During a scalp biopsy, a small sample of scalp skin is taken and examined under a microscope to identify the cause of hair loss.
- Pull or tug test: A doctor gently pulls hair strands to check how much hair is shedding. Losing 50 to 100 hairs per day is considered normal.
- Medical history: A review of dietary habits, hair care routines, family history, and overall health can help identify possible causes of hair loss.
- Physical exam: A doctor examines the scalp and hair to check the pattern of hair loss and look for signs of infection or other skin conditions.
- Card test: This involves dragging a small card against the hair to differentiate the newly growing hairs from the broken hairs.
- Trichometric analysis: This test uses a digital tool to measure hair density, growth rate, and thickness, helping assess overall hair health and condition.
When to see a doctor
If you’re experiencing excessive or unexplained hair loss, it’s important to see a doctor. Hair loss can sometimes indicate an underlying health condition that needs attention.
You should consider seeing a doctor if you experience:
- excessive shedding
- sudden or patchy hair loss
- thinning across the scalp
- hair loss after starting new medications
- scalp symptoms like redness, itching, or pain
- other symptoms like fatigue, weight changes, or menstrual irregularities
Getting early medical help allows your doctor to run the necessary blood tests for hair loss and identify the cause.
Takeaway
Blood tests for hair loss can identify underlying conditions, such as hormone imbalances or nutrient deficiencies, such as low iron or vitamin D.
When combined with other tests like scalp biopsies or trichometric analysis, blood tests help doctors evaluate hair health.
If you’re experiencing persistent or unexplained hair loss, consider talking with a doctor to find the appropriate blood test for your condition.
