High street vitamin D test kits give the SAME person results ranging from deficient to sufficient, consumer watchdog Which? warns

Which? purchased five rapid finger-prick vitamin D test kits — from Boots, Berkeley Health, MyHealthChecked, OneStep and Newfoundland — and measured their results against a CQC-registered lab blood test conducted on the same day. While the lab test placed the tester comfortably in the sufficient range, the five kits produced three contradictory verdicts.

Two of the kits classified the tester as deficient — a finding the Royal College of Pathologists warns can indicate a genuine health risk.

The rapid kits apply a sufficiency threshold of 75nmol/L, well above the NHS benchmark of 50nmol/L, so they are more likely to flag users as falling short.

Which? cautions that inaccurate readings could lead consumers to take high-dose supplements unnecessarily, potentially driving calcium levels in the blood to dangerous heights.