What are the recommended initial investigations for diagnosing hypoparathyroidism in adults?

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Posted: 16 August 2025Updated: 16 August 2025 Guideline-Aligned (High Confidence) Clinically Reviewed
Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX

Recommended initial investigations for diagnosing hypoparathyroidism in adults include:

  • Measurement of serum calcium, specifically albumin-adjusted serum calcium, to identify hypocalcaemia (low calcium levels) which is a hallmark of hypoparathyroidism.
  • Measurement of serum parathyroid hormone (PTH) levels concurrently with calcium to confirm low or inappropriately normal PTH in the context of hypocalcaemia, which supports the diagnosis of hypoparathyroidism.
  • Assessment of serum phosphate, as hypoparathyroidism typically presents with hyperphosphatemia (elevated phosphate levels).
  • Measurement of serum magnesium, since hypomagnesemia can cause functional hypoparathyroidism and should be corrected.
  • Vitamin D levels should be measured to exclude vitamin D deficiency as a cause of hypocalcaemia.

These tests are essential to differentiate hypoparathyroidism from other causes of hypocalcaemia and guide further management.

Educational content only. Always verify information and use clinical judgement.