C-peptide testing helps distinguish type 1 from type 2 diabetes. Which statement is correct?

• A. High C-Peptide levels indicate Type 1 diabetes
• B. C-Peptide testing cannot differentiate diabetes types
• C. Low or absent C-Peptide suggests Type 1 diabetes
• D. C-Peptide is elevated in Type 1 diabetes only

Answer: (C)

C-Peptide reflects how much insulin the body is still producing on its own, so it helps distinguish autoimmune destruction from insulin resistance. In type 1 diabetes, the immune system attacks the beta cells, leading to little or no insulin production, which shows up as low or absent C-Peptide. In type 2 diabetes, insulin production is often preserved or even increased early on as the body compensates for insulin resistance, so C-Peptide is typically normal or elevated. Therefore, the statement that low or absent C-Peptide suggests type 1 diabetes best captures how this test helps differentiate the two forms.