Diabetes Mellitus - Diagnosis.
Diabetes Mellitus (DM) is a persisting state of hyperglycemia due to lack or diminished effects of insulin.
Diabetes can be diagnosed by analysing the blood samples of a patient. In the hospital laboratories they can carry out test to determine the blood glucose levels of a patient. The World Health Organisation (WHO) set diagnostic criteria for all doctors to follow. The description of these test are described below.
The WHO Diagnostic Criteria:
Two fasting venous plasma glucose levels >7.8 mmol/ L establishes that the patient may have diabetes.
If on two fasting blood glucose tests, the sugar concentration is >6mmol/L but < 8mmol /L there may be impaired glucose tolerance or Diabetes Mellitus.
An Oral Glucose Tolerance Test should be carried out, and dietary advice is normally given.
N.B. Fasting venous plasma glucose, implies that the patrinets blood sample was taken after not eating for 15hrs. e.g. taking the blood sample first thing in the morning before the patient has breakfast. There last food being the previous evenings meal.
Oral Glucose Tolerance Test: 
The patient has to fast for 15 hours. 6 hours before the test the patient should avoid smoking and drinking coffee. Fasting blood glucose is measured.
The patient then drinks 75g of glucose in 300ml of water.
Blood glucose is then measured every 30 seconds for five minutes. A urine sample is collected before the drink and after 60 and 120 minutes after drinking the sugar solution.
What they results tell the doctor.
If the 120 minute blood sample shows plasma glucose <7.8mmol/l, Diabetes Mellitus and Impaired Glucose Tolerance (IGT) are excluded.
If plasma glucose >7.8, but <11.1 mmol/l there is IGT.
If plasma glucose >11.1mmol/l there is Diabetes Mellitus.
In practice the Oral glucose Tolerance Test is not often needed.
Type I - Insulin Dependent Diabetes Mellitus.
This type usually starts in childhood, however it can start at any age. Factors indicating that insulin may be needed are blood glucose concentration >25mmol / l, sudden onset, weight loss and dehydration.
Type II. Non- Insulin Dependent Diabetes.
It has a stronger genetic component than type 1. It may occur in the obese or non -obese.
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