SACB members should write to MOH for a copy of the guidelines if there is not one available in their laboratory for reference.   

Dr. Chen Ai Ju, Director of Medical Services at a symposium on this guideline said, "Diabetes mellitus (DM) is an important health problem world wide and it is estimated that the number will more than double, from 140 million to 300 million, in the next 25 years." She urged primary care doctors to use the guideline as "one in 10 visits in polyclinics (about 350,000 a year) are attributable to DM".   

How will this guideline impact laboratory diagnosis?   
The new diagnostic criteria will change interpretation, thus putting the prevalence of DM in Singapore at 10.0% instead of 9.0%. In addition, 14.3% would be diagnosed as impaired glucose tolerance and 5.7% impaired fasting glycemia. More patients will be screened for DM and doctors will also use laboratory results to focus on underlying complications, such as dyslipidemia and microalbuminuria. Highlights of the guidelines are summarised below.   

1. The diagnosis criteria for DM according to the new guidelines are fasting plasma glucose (FPG) >= 7.0 mmol/L, casual plasma glucose >=11.1 mmol/L and 2 hour oral glucose tolerance test (2 hour-OGTT) level >=11.1 mmol/L. The intermediate group with FPG 6.1 to 6.9 mmol/L should undergo a 75 gram OGTT. Diagnosis should be made on a venous plasma glucose level estimated by a laboratory using a reference method while glucometer results can be used for screening the patient only.   

2. Screen all individuals >= 40 years and younger individuals with body mass index is >= 27 kg/m2, blood pressure >= 140/90 mmHg, a first degree relative with DM, previous gestational DM (GDM) and coronary artery diseases. Screen normal individuals at 3 year intervals or more frequently as indicated. Screen those with impaired fasting glycemia or impaired glucose tolerance annually.   

3. Aim for "optimal" glucose control of HbA1c 6.5 to 7.0% and preprandial glucose 6.1 to 8.0 mmol/L. "Suboptimal" glucose control (HbA1c 7.1 to 8.0% and preprandial glucose 8.1 to 10.0 mmol/L) may be the target in special subsets of patients such as elderly patients and individuals with advanced diabetic complications or other co-morbidities. The glycemic treatment goal of HbA1c should be 4.5 to 6.4% for pregnant women with pre-existing or existing GDM. The glucose values indicated pertain to capillary blood samples and the guidelines emphasised that the patients should be trained by qualified staff to operate the glucometers, to interpret the results and to modify treatment accordingly. The guidelines also recommend periodic reviews by comparing simultaneous results obtained by the users and clinics to the reference laboratory.   

4. The threshold to initiate treatment for dyslipidemia in a diabetic patient with or without coronary artery disease (CAD) is a lipid profile of total cholesterol (TC)>= 5.2 mmol/L,LDL-C >= 3.5 mmol/L, and triglycerides (TG) >= 2.3 mmol/L. Aim for target levels of TC 4.5 mmol/L, LDL-C 2.5 mmol/L, and TG 1.0 mmol/L   

5. Screen for microalbuminuria as this is an important risk factor for the development of progressive diabetic nephropathy. Microalbuminuria is defined as either an albumin concentration of 20 - 200 mg/L or an albumin:creatinine ratio of > 3.5 (women) and > 2.5 g/mmol (men) on a random urine sample (ideally first void), an albumin excretion rate of 20 - 200 mg/min on a timed urine collection (4 hours or overnight) or 30 - 300 mg in a 24 hour collection. If a urine dipstix is positive, proceed to 24 hour urine total protein and creatinine clearance tests.