Blood Tests for Diabetes

People with Diabetes have to come to terms with testing their blood glucose (BG) every now and then. It becomes a part and parcel of daily life. A must, if good control is desired. Apart from testing blood glucose several times a day, there are many other blood tests that are specific to Diabetes. Here’s a brief look at some of them;  
 
OGTT or Oral Glucose Tolerance Test is a test for diagnosis of Diabetes. A water solution with 75 gm of glucose is given to the patient and his/her blood sugar is measured before drinking & at 1 & 2 hours after drinking the glucose load. Some doctors may measure every 1/2 hour to get a more detailed analysis of the blood sugar pattern.  
 
Hb-A1c or Haemoglobin A1c test is also a diagnosis tool which generally maps to the Blood Sugar profile of a patient for the past 90-120 days. Haemoglobin in blood has many sub-types and the A1c type of cells are the ones which have glucose attached to them. Hb-A1c Also known as the glycated hemoglobin test, may be ordered by doctors every 3-6 months for diabetic patients. Home self-test kits for Hb-A1c are also available in some markets. RBC contains hemoglobin cells that also have many sub types. The BG has a tendency to get stuck to the “A1” type of hemoglobin cells, where after they are classified as A1c type cells. The percentage of these cells among the total Hb cells is measured in the test. Lately, A1c monitoring & reporting is also being done in mmol/mol or millimoles per mole in some parts of the world.  

FASTING This is a test for blood glucose (BG) without eating or drinking anything (except water) for the past 8 hours at least. Normally this is a test conducted every morning upon waking up. Delaying the test for some time might result in BG getting elevated.

PRE-MEAL : These BG tests are to be taken before starting to eat a meal. It can also be considered as a fasting test if the 8 hour intake restriction has been followed.  
 
POST-PRANDIAL : These are BG tests to be carried out at various times after eating meals. Some people consider it from the time of first bite, while others time it after finishing the meal. The tests can be conducted as soon as 15 minutes after the meal, but normally PP tests are done at 1 hr & 2 hr after meals. Insulin secretion by the pancreas takes place in 2 phases. The 1st phase is the rapid release of the stored insulin since the last meal. After this comes the 2nd phase which is the slow release of freshly produced insulin. These phases correspond to the 1 hr & 2 hr mark, hence the timings of the test.  

RANDOM : These are BG tests to be carried out at any time during the day or night. Therefore they are known as random tests. Such tests can be used to see the effect on BG of things like exercise, illnesses, other drugs being consumed. Workout training sessions or exercise activities can be tested for its nature, intensity or duration.  
 
C-PEPTIDE : The beta cells of the pancreas produce a hormone known as proinsulin which splits up into two molecules, one each of Insulin and C-peptide. The C-Peptide thus serves as an ideal proxy for the measurement of insulin released by the pancreas. Direct insulin assays have also been introduced by many labs around the world. These tests are used to measure insulin production / secretion.  
 
GAD 65 : Antibodies test is carried out for determination of autoimmune disorder during diagnosis of Diabetes. The GAD65 (glutamic acid decarboxylase) antibodies are pancreatic islet antibodies and indicate that the pancreatic beta cells are under constant attack by the body’s own immune system. Type 1 and LADA determination can be confirmed by the presence of these antibodies in the blood.