Screening for Diabetes Mellitus

Screening should be considered in adults of any age who have one or more risk factors for diabetes. In those without risk factors , testing should begin at 40 years. Those between 18-39 years old can consider doing the Diabetes Risk Assessment Tool (DRAT) on the HealthHub website or the HealthHub app to assess their risk of getting Diabetes. Those who have been found to be high risk using the DRAT assessment should undergo formal blood test screening.

Diabetes Risk Assessment Tool

Diabetes Screening (CDMP Handbook guidelines)⁵

The recommended investigations for screening of diabetes in asymptomatic individuals aged ≥40 and/or with risk factors for diabetes are as follows:

Fasting plasma glucose (FPG)
HbA1c (not suitable for those with haemoblobinopathy)

Asymptomatic individuals with a result suggestive of Diabetes Mellitus based on the above tests should have a repeat test on a subsequent day. For these patients, when two different tests are available and the results are above the diagnostic thresholds, the diagnosis of diabetes is confirmed.

If HbA1c is used as the screening test, the following interpretation and follow-up testing is recommended.

Table. Summary of HbA1c Screening Guidelines⁵

	HbA1C Screening	Interpretation	Action	Recommended Diagnosis
High risk of DM OR Age ≥ 40 years	6.0% and below	Low probability of diabetes.	No further tests needed if there are no symptoms of diabetes.* Further testing with an FPG or 2hOGTT is recommended in the presence of clinical suspicion of diabetes.	No Diabetes Maintain healthy lifestyle and weight. Repeat test in 3 years.
	6.1% to 6.9%	Proceed to FPG or OGTT	FPG≤ 6.0mmol/L OR 2hOGTT < 7.8mmol/L
			FPG 6.1-6.9 mmol/L OR 2hOGTT 7.8-11.0 mmol/L	Pre-diabetes Manage as per Appropriate Care Guidelines (ACG).
			FPG ≥7.0mmol/L OR 2hOGTT ≥ 11.1mmol/L	Diabetes Manage Accordingly
	7.0% and above	High probability of diabetes	No further tests needed.	Diabetes Manage Accordingly

* Symptoms of diabetes mellitus include: frequent urination, increased thirst, weight loss with no obvious cause, frequent skin infections, slow wound healing and blurring of vision. Of note, these symptoms are not specific for diabetes.

Screen women without any pre-diabetes or diabetes history at 24 to 28 weeks of gestation using 3-point 75 g OGTT. Re-evaluate high-risk women who had normal test results in their first trimester. (Refer to ACE Guidelines on Gestational Diabetes Mellitus.)