Diabetes Tests

Question 1. What is Diabetes?

Diabetes is high glucose disease. High glucose in blood is unhealthy as it causes water and electrolyte loss in  kidneys and in the long term damages many organs systems such as kidneys, heart, brain  and nerves resulting end organ failures such as kidney failure, heart attack or stroke.

Diabetes is a Western disease and is increasing amongst Town and city dwellers of PNG who depend on processed foods combined with lack of physical activity and adoption of certain habits such as alcohol consumption and smoking. 

The major cause of diabetes is lack of or inadequate insulin required by body to handle glucose properly. Insulin is a hormone produced by pancreas, a gland next to your stomach and spleen below the left rib margin. Insulin helps body mob up glucose from diet and in circulation into tissues for energy production and storage. Rarely, diabetes is due to causes other than insulin deficiency such as Cushing's syndrome (high cortisol) and hyperthyroid (high thyroid hormones).

Traditionally diabetes is classed as type I (early onset) or type II (late onset). Type one diabetics occurs early in life and they lack enough insulin whereas type II is due to increased tissue resistance to insulin so that extra insulin than normal is required to handle glucose by tissues.

Fortunately early detection and diagnosis of diabetes and effective treatment is available to prevent early death or long term complications.

 Question 2. When should I suspect if I have Diabetes?

According to western data, 50% of diabetes remains undiagnosed. That means you may not know that you have diabetes unless you get tested. Many more are diagnosed incidentally when assessed for unrelated problem or when they arrive with complications of diabetes such as  dehydration, hypertension, kidney disease, stroke and heart attack.

 It is important that regular blood tests for diabetes (every 3 years minimum) even if you do not have any symptoms. However, following are definite indications for diabetic screen.

Anyone >45 years old

Family history of diabetes

Increased thirst and urge to urinate  >5-6x /day

Weight loss

Over-weight

Infertility

Menstrual disorders

Pregnancy

Recurrent boil /abscess or skin infection

Recurrent Candida infection/thrush (genital itch or heavy discharge)

Tingling/numbness/abnormal sensation of feet

Heart Pain

Visual disturbance (blurring)

High blood Pressure

Kidney disease

 Question 3. How is Diabetes diagnosed?

The two commonly used tests for diabetes screen called fasting glucose and glucose challenge test. More recently HbA1c has been included as an alternate marker for  diagnosis of diabetes (see Question 14 below). Fasting glucose is easier and simpler to perform than glucose challenge. It requires a sample of blood after 9-12hours of fasting. For glucose challenge is usually used in pregnancy diabetes screen. There is no special preparation for glucose challenge test although you are advised to avoid eating or smoking at least 2 hours prior to testing. This test involves drinking a solution of glucose 1 hour prior to checking glucose level. Written instruction is usually given at the time of booking.  See further information on Pregnancy Screen for Diabetes and Full Oral Glucose Tolerance Test.

 Question 4. How is the test performed?

You will fast 9-12hours before blood sample is taken. You will then present next morning before breakfast for a small blood sample (about 5-10mls) via puncher of vein. Serum or plasma sample is required for measurement of glucose. Whole blood glucose is affected by haematocrit (number of circulating red cells) and is not used to establish a diagnosis. Capillary blood is not suitable for diagnosis as it is 10-15% lower. Any raised level on capillary blood like that measured by finger pricking should be confirmed on laboratory testing.  . This is enough to test for other basic chemistry tests including kidney, liver, pancreas, gout, calcium , cholesterol and cancer blood tests-if required.

 Question 5. Is there any pitfall to the tests?

Common problem with glucose measurement include falsely high and false low glucose. Inadequate fasting or blood taken during states of acute stress (e.g. severe infection) is the commonest cause of high glucose. Diabetes can be missed if blood is not collected in appropriate tube with preservatives and  delay in transport and separation of blood cells. In addition, use of wrong reference levels may cause error in your results. As diabetic diagnosis criteria changes frequently as more research data becomes available you should ensure that your doctor or laboratory is up-to-date on diabetes diagnosis. 

 Question 6. How long before the results available?

The test are very simple and takes only few minutes. It can take 1-2hours depending on laboratory workload. You should return to your doctor on the next appointment day for discussion of results. Patient or doctor will be contacted for urgent results. All reports are kept confidential and only accessed by patient or his/her doctor.  

 Question 7. What does my test report mean?

Your results will be reported as normal, possible diabetes or consistent with diabetes. Those with results suggestive but not diagnostic of diabetes will undergo further test called Full Oral Glucose Tolerance test or FOGTT.  Summary of current WHO diagnostic criteria on fasting glucose is given below.

Fasting glucose < 5.5mmol/L is normal/diabetes unlikely

Fasting glucose 5.5-7.8mmol/L —impaired fasting glucose, requires FOGTT for exclusion of diabetes mellitus

Fasting glucose >7.8mmol/L —consistent with diabetes mellitus especially if you have symptoms

It is recommended that the results should be confirm on two separate occasions or days.

 Question 8. My random glucose is high. Am I diabetic?

This depends on the level of your blood sugar and whether or not you have symptoms of diabetes. If your random blood sugar level is more than >11.1mmol/L and have symptoms of diabetes as given above,  you are probably diabetic. In this case, FOGTT is unnecessary and may be dangerous for you.  If your random glucose level is between  5.5mmol/L and 11.1 mmol/L, you need to repeat your blood sugar by fasting as above or see your doctor to arrange for Full Oral Glucose  Tolerance test to see if you are diabetic. For diagnosis of diabetes, it is recommended that fasting or random levels should be confirmed on two separate occasions preferably two different days.

 Question 9. Can Urine Test be used for diagnosis of diabetes?

No. Urine testing is not a good test for diagnosing diabetes. Urine test may be normal even if you have diabetes. Any positive sugar test in urine requires blood test for confirmation of diabetes.

Question 10. I have high sugar level on finger pricking. Am I diabetic?

Finger pricking  can be used for screening for diabetes  but should not be the only method for establishing diagnosis. Any high level should be confirmed by laboratory based testing. You may still be diabetic even if finger prick test is normal.

 Question 11. What is the Treatment?

Treatment of diabetes is involves oral tablets or injection of insulin. There are various regimens available and you should discuss these options with your doctor.   Off-course weight control and monitoring of your diet also helps control your blood glucose level and prevent early onset of complications. General diet advice include, more vegetables, fish and fresh fruit based diet and less processed or tinned food. Discuss with your doctor for further assistance and click here to learn more on your ideal body weight.

 Question 12. Why do I need repeat blood or urine checks while on treatment?

Close monitoring is a requirement in diabetes management to prevent early death from complications. Firstly, diabetes is a multi-system disease  and affects many organ systems and metabolic processes. It is important that you have regular checks so your doctor can pickup problems early and treated accordingly. You need your kidneys, electrolytes, and body fat (cholesterol & triglycerides) monitored. Secondly, your sugar levels needs monitoring to pick up any abnormal swings (hypoglycaemia) or hyperglycemia) while you are on treatment. Finally, regular blood testing will also assist your doctor decide how well you are responding to diabetes treatment given and make adjustment where necessary.

 Question 13. How is my diabetes monitored?

Studies have shown that good control of diabetes not only improves immediate well-being but more importantly prolongs onset of complications of diabetes as kidney disease, stroke, heart attack, neuropathy and blindness. 

 Short-term measures include measurement of blood glucose, urea and creatinine and electrolytes as well as urine ketones and protein (microalbumin). However, measuring glucose alone is not good test for assessing effectiveness of your diabetic treatment and risk of you developing complications.

 A protein called HbA1c measurement is the best test for monitor effectiveness of diabetes treatment. It shows how well your diabetes control has been over the last 3 months. If your HbA1c is >8%, your diabetes is poorly controlled and you are at risk of early death from complications such as kidney failure, heart attack  and stroke. You need to talk to your doctor about further adjustments to your treatment regimen. If your clinic or doctor do not provide this test, you are being offered sub-standard care! At the time of writing, no doctor in PNG including the few diabetic clinics in PNG perform HbA1c testing!

 Question 14. Can HbA1c be used to make diagnosis of diabetes mellitus?

Yes. Recent evidences suggest use of HbA1c as an alternate if not better marker for diagnosis of diabetes. Since 2009, various organizations including WHO, International Expert Committee on HbA1c and American Diabetic Association have all released guidelines recommending the use of HbA1c in diagnosing diabetes mellitus. They recommend hbA1c cut-off level of >6.5% as an indication for diagnosis of diabetes and suggest that this should be confirmed by repeat testing on at least 2 occasions unless patient has sign and symptoms of diabetes or blood glucose also supports the diagnosis of diabetes. The advantage of measuring HbA1c is that fasting is not necessary and can be measured at any time of the day. It does not fluctuate as much as glucose and it represents an average blood glucose of patient over the last 2-3months. The main problem is that HbA1c measurement is expensive and  is not widely available in most centres in PNG.

 Question 15. What are Ketone bodies?

Ketone or ketone bodies are end products of fat when it is breakdown. When you have no insulin, your body switches to other sources of energy such as fat. When large amount of fat is broken down for energy, ketones are released. When these build up in blood it can reach dangerous levels to cause your blood to become more acid and cause abnormal electrolyte  changes putting you at risk of death. By monitoring ketones in urine and blood ,doctors are able to assess severity of diabetes and institute appropriate emergency treatments.