Routinely testing for C-peptide when patients with type 1 diabetes visit their treating doctor might result in some of them being diagnosed with a different type of diabetes, researchers say.

Endocrinologists from an outpatient clinic in Edinburgh, Scotland, tested non-fasting C-peptide levels when patients diagnosed with type 1 diabetes mellitus (T1DM) for at least three years came for a routine consultation.

C-peptide levels of below 0.2nmol/L were considered indicative of severe insulin deficiency thus confirming the T1DM diagnosis.

But if patients had a C-peptide measurement greater than 0.2nmol/L, further investigations were carried out, depending on the level of the biomarker.