What blood tests are recommended for a vegan female patient in her 40s or 50s with a history of Premenstrual Dysphoric Disorder (PMDD), low iron, and vitamin D deficiency, presenting with symptoms of fatigue, brain fog, mood instability, hair thinning, and menstrual cycle changes, to assess nutritional deficiencies, thyroid function, hormonal changes, autoimmune markers, and metabolic health?

Recommended Blood Tests for Comprehensive Health Assessment in Perimenopausal Vegan Female with PMDD History

For a vegan woman in her 40s-50s with PMDD history presenting with fatigue, brain fog, mood instability, hair thinning, and menstrual changes, the following blood tests should be ordered to assess nutritional deficiencies, thyroid function, hormonal status, autoimmune markers, and metabolic health:

Essential Nutritional Assessment

Iron Studies (Priority Testing)

• Full blood count (FBC) with hemoglobin and red cell indices 1
• Serum ferritin (most powerful test for iron deficiency; threshold <45 ng/mL indicates deficiency) 1
• Transferrin saturation (helpful when ferritin is borderline or inflammatory conditions present) 1

Iron deficiency is extremely common in premenopausal women (39% prevalence) and even more so in vegans due to lower bioavailability of non-heme iron 1. Given your history of low iron, this is the highest priority nutritional assessment 1.

Vitamin B12 and Folate

• Serum vitamin B12 1
• Serum folate 1

Vitamin B12 deficiency is critical to assess in vegans as plant-based diets lack reliable B12 sources 1. B12 deficiency can cause fatigue, brain fog, and mood changes—symptoms overlapping with your presentation 1.

Vitamin D

• 25-hydroxyvitamin D [25(OH)D] 1, 2

Vitamin D deficiency is common in the general population and particularly relevant given your history of low vitamin D 1. Levels below 50-75 nmol/L (20-30 ng/mL) indicate deficiency 1. Notably, women with PMDD have been shown to have significantly lower 1,25-dihydroxyvitamin D during the luteal phase, which may contribute to PMDD symptoms 2.

Calcium Metabolism

• Serum calcium (total and ionized) 2
• Intact parathyroid hormone (PTH) 2

Women with PMDD demonstrate significantly lower ionized calcium levels and altered calcium-regulating hormones across the menstrual cycle 2. These abnormalities may be responsible for affective and somatic symptoms in PMDD 2.

Thyroid Function Assessment

• Thyroid stimulating hormone (TSH) 1
• Free T4 1
• Free T3 (if TSH abnormal) 1

Thyroid dysfunction presents with fatigue, mood changes, hair thinning, and menstrual irregularities—symptoms identical to your presentation 1. Routine screening is particularly important given the overlap of symptoms 1.

Autoimmune Screening

Celiac Disease

• Tissue transglutaminase antibody (anti-tTG IgA) 1
• Total IgA (to exclude IgA deficiency which makes anti-tTG unreliable) 1

Celiac disease screening is essential as it causes iron deficiency, fatigue, and nutrient malabsorption 1. Undiagnosed celiac disease is a common cause of persistent iron deficiency despite supplementation 1.

Thyroid Autoantibodies (if thyroid dysfunction detected)

• Anti-thyroid peroxidase (anti-TPO) antibodies 1
• Anti-thyroglobulin antibodies 1

Metabolic Health Assessment

• Comprehensive metabolic panel (glucose, electrolytes, kidney function, liver function) 1
• Fasting lipid profile (total cholesterol, LDL, HDL, triglycerides) 1
• Hemoglobin A1c (for glucose assessment) 1

These tests assess cardiovascular risk and metabolic syndrome, which become increasingly important in perimenopausal women 1.

Additional Considerations

Homocysteine

• Serum homocysteine 1

Elevated homocysteine can occur with B12 or folate deficiency and is associated with various neurological symptoms including cognitive impairment 1. This is particularly relevant given your brain fog symptoms 1.

Magnesium

• Serum magnesium 1

Low magnesium has been linked to muscle fatigue and correlates with self-reported fatigue 1.

Important Clinical Caveats

Ferritin interpretation: Ferritin is an acute-phase reactant and may be falsely elevated in inflammatory conditions 1. If ferritin is between 45-100 ng/mL with ongoing symptoms, consider transferrin saturation or soluble transferrin receptor for confirmation 1.

Timing of testing: For hormonal assessments related to perimenopause (FSH, estradiol), these should be timed appropriately with menstrual cycle if still cycling regularly 3.

H. pylori testing: If iron deficiency is confirmed and persists despite supplementation, non-invasive H. pylori testing should be considered as it can impair iron absorption 1.

Avoid routine testing of: Faecal occult blood (insensitive and non-specific for iron deficiency assessment) 1, and routine coagulation studies unless clinically indicated 1.

Medicare MBS Eligibility

All tests listed above are covered under Medicare MBS in Australia when clinically indicated based on your presenting symptoms and risk factors (vegan diet, previous deficiencies, PMDD history, perimenopausal symptoms) 1.