A 32-year-old woman reports spoon-shaped nails that are concave dorsally with everted lateral edges. Which laboratory investigation is most appropriate first?

• A Serum ferritin and haemoglobin ✓
• B Thyroid stimulating hormone
• C Serum calcium and phosphate
• D Antinuclear antibody titre

Explanation

Koilonychia, the spoon nail deformity, is classically associated with iron deficiency anaemia and also occurs in Plummer-Vinson syndrome and haemochromatosis. It may be physiological in children and occupational in wet workers. Checking iron studies first is therefore correct. Hypothyroidism links to brittle slow-growing nails rather than spooning, and calcium disorders produce no characteristic nail shape change.

Reference: Fitzpatrick's Dermatology, 9th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.