Screening should be considered in adults of any age who have one or more risk factors for diabetes mellitus (DM). In those without risk factors , testing should begin at 40 years old. 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 DM. 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 DM in asymptomatic individuals aged ≥40 and/or with risk factors for DM are as follows:

  1. Fasting plasma glucose (FPG)
  2. HbA1c (not suitable for those with haemoglobinopathy)

Asymptomatic individuals with a result suggestive of DM 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 DM 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 


Age ≥40 years


6.0% and below

Low probability of DM.

No further tests needed if there are no symptoms of DM.*

Further testing with an FPG or 2-hr oral glucose tolerance test (OGTT) is recommended in the presence of clinical suspicion of DM.


Maintain healthy lifestyle and weight. Repeat test in 3 years.

6.1% to 6.9% Proceed to FPG or 2-hr OGTT.

FPG ≤6.0 mmol/L

OR 2-hr OGTT <7.8 mmol/L

FPG 6.1-6.9 mmol/L

OR 2-hr OGTT 7.8-11.0 mmol/L


Manage as per Appropriate Care Guidelines (ACG).

FPG ≥7.0mmol/L

OR 2-hr OGTT ≥11.1 mmol/L


Manage Accordingly

7.0% and above High probability of DM No further tests needed.

* Symptoms of DM 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-DM or DM​ 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.)