What are the recommended screening protocols for diabetic nephropathy in patients with type 1 and type 2 diabetes?

For both type 1 and type 2 diabetes, the recommended screening protocol for diabetic nephropathy involves annual monitoring ⁵.

• Key Tests:
  • The primary test for detecting proteinuria is the urine Albumin:Creatinine Ratio (ACR) ⁴. ACR is preferred over protein:creatinine ratio (PCR) due to its greater sensitivity for low levels of proteinuria ⁴.
  • An estimated Glomerular Filtration Rate (eGFR) should be measured at the same time as the ACR ³.
• Sample Collection:
  • For adults with type 1 diabetes, and children and young people with type 2 diabetes, the first urine sample of the day ('early morning urine') should be used for ACR measurement to reduce the risk of false positive results ³,⁵.
  • If an early morning urine sample is not available for children and young people, a random sample can be used, but it carries an increased risk of false positive results ⁵.
• Interpreting and Confirming Results:
  • A confirmed ACR of 3 mg/mmol or more is considered clinically important proteinuria ⁴.
  • If the initial ACR is between 3 mg/mmol and 70 mg/mmol, it should be confirmed with a subsequent early morning urine sample ⁴.
  • For children and young people, if the initial ACR is above 3 mg/mmol but below 30 mg/mmol, the result should be confirmed by repeating the test on two further occasions using early morning urine samples before initiating further investigation or therapy ⁵.
  • A repeat sample is not needed if the initial ACR is 70 mg/mmol or more ⁴.
  • Further investigation is required if the initial ACR is 30 mg/mmol or more in children and young people ⁵.
• Related Screening (Hypertension):
  • Children and young people with type 2 diabetes should be screened annually for hypertension [NICE, 2020b] ¹,².
  • Blood pressure should be checked at least annually in adults with type 2 diabetes without previously diagnosed hypertension or renal disease [NICE, 2019a] ¹,².