C- PEPTIDE TEST FOR DIABETES..

What Is C Peptide?

Insulin is responsible for regulating the body's glucose levels. Glucose, the body's main source of energy, is a sugar that comes from foods. After a meal, our bodies break down the foods we eat into glucose and other nutrients, which are then absorbed into the bloodstream from the gastrointestinal tract. Insulin works like a key that opens the doors to cells and allows the glucose in. Without insulin, glucose can't get into the cells and it stays in the bloodstream. The most common cause of abnormal fluctuations in blood glucose is diabetes. Glucose levels in the blood rise after a meal and trigger the pancreas to make insulin and release it into the blood. When insulin is released, so is C-peptide.

C-peptide is a chain of proteins that is spun off in the process by which the beta cell makes insulin in pancreas.. During this process, a precursor molecule, proinsulin is split into insulin and C-peptide. So for every molecule of insulin your beta cells produce, they also produce a molecule of C-peptide. C-peptide, on the other hand, has no effect on blood sugar. It is, however, useful as a marker of insulin production, since the pancreas typically releases C-peptide and insulin in about equal amounts.

A C-peptide test measures the level of this peptide in the body. In general, high C-peptide levels are associated with increased insulin production, while low C-peptide levels indicate decreased insulin production.

Why It's Done

The C-peptide test may be ordered to determine how much insulin is being made by the pancreas. This information is useful because:

1.It can help doctors tell the difference between type 1 and type 2 diabetes. In type 1 diabetes, the pancreas produces little or no insulin and little or no C-peptide. In type 2 diabetes, C-peptide levels will typically be normal or high, as the pancreas works harder to overcome insulin resistance by producing more insulin.

2. A C-peptide test can also help find the cause of low blood sugar (hypoglycemia), such as excessive use of medicine to treat diabetes or a noncancerous growth (tumor) in the pancreas (insulinoma).

3.Check to see whether a tumor of the pancreas (insulinoma) was completely removed.

C-peptide is removed from the bloodstream by your kidneys while insulin is removed by the liver. This makes a difference in how long these peptides stay in the bloodstream. It takes half an hour until C-peptide is removed, while insulin is gone in five minutes. This means that there should be five times as much C-peptide in your blood at any given time as there is insulin and the longer activity period should smooth out the effects of testing at any one particular moment.

However, if there is something wrong with your kidneys they may not remove C-peptide in a normal manner and the result of a C-peptide test may be misleading. If a person is injecting insulin, measuring C-peptide is the only way doctors can determine whether they are also making insulin on their own since lab tests do not distinguish between injected insulin and homemade.

The main thing a C-peptide test tells you is whether or not your body is making C-peptide. But in fact, that really is all that the test tells us. This can be useful in itself--if there is no C-peptide in a blood sample, your beta cells are not making any insulin. A very low C-peptide result is the definitive way to diagnose severe Type 1 diabetes--though many people with Type 1 will continue to have a low level of C-peptide in their blood for years after diagnosis as good control started soon after at Type 1 diagnosis appears to keep a small number of their beta cells alive.

To derive more meaning for the results of a C-peptide test the lab must know whether it was taken fasting or not fasting and what the blood glucose level was at the moment it was taken. In theory, a high fasting blood sugar with a high C-peptide value should point to Type 2 diabetes primarily caused by insulin resistance. That is because the high C-peptide value would suggest a lot of insulin was being produced but insulin resistance was keeping it from lowering blood sugar.

In contrast, a C-peptide value that was normal or below normal taken at the same time as a high fasting glucose would suggest a form of Type 2 where failing beta cells rather than insulin resistance was the primary thing raising blood sugar. In theory, testing C-peptide very few years should also give you some idea of whether or not your beta cells are slowly failing.

Unfortunately, there is no standardization in the way that labs measure C-peptide or in the reference ranges they provide. It is usually suggested that because of the different test protocols and reference ranges in use, you use the same lab to compare C-peptide values, when trying to determine if your C-peptide levels are dropping.

With this in mind, here's what your C-peptide can tell you:

The normal fasting C-peptide value is given as 0.51–2.72 nanograms per milliliter (ng/mL) or 0.17–0.90 nanomoles per liter (nmol/L)

1. Very Low C-peptide test results. If your CC-peptide is significantly below the normal fasting range given by your lab no matter when your blood sugar was tested your beta cells are likely to be dead or dying. If you are young or very recently diagnosed with diabetes of any type, a very low C-peptide value is a good way of diagnosing Type 1 (autoimmune) diabetes. Low levels of both C-peptide and blood glucose are found in liver disease, a severe infection.

But if you have had Type 2 for decades, and have not kept your blood sugars at normal levels, you may also have a very low C-peptide test value because over the years the very high blood sugars you have been exposed to may have killed off your insulin-producing beta cells.

2. High Fasting C-peptide test results. A high fasting C-peptide test value taken at the same time as a high fasting blood glucose test value suggests that you are insulin resistant though still making lots of insulin. . Normal or high levels of C-peptide in combination with high blood glucose may indicate that the body is producing enough insulin but the cells are not responding to it properly. More insulin is made in obese people and can cause high levels of C-peptide

If your fasting C-peptide level is high, it is very likely that you will be able to control your blood sugar by cutting way down on the amount of carbohydrate you eat. It also means that you should first try strategies that lower insulin resistance before trying sulfonylurea drugs that stimulate more insulin release.

If you have high fasting C-peptide levels, the drug Metformin, which increases insulin sensitivity, should be helpful in lowering your blood sugar. Exercise may also be very helpful as many people (though not all) find it temporarily reduces insulin resistance.

3. Non-fasting C-peptide test results. If your non-fasting C-peptide test is not abnormally low (pointing to completely dead beta cells) there is no accurate way to interpret a non-fasting C-peptide test result. This is partly due to the non standardisation of this test across labs and the fact that most labs do not give any lab reference range for non-fasting values.

Normal or High C-Peptide Test Results May Be Good News.

C peptide test helps to:

•Determine the effectiveness of a pancreas transplant or islet cell transplant. These transplants are performed to promote the production of insulin. By measuring the C-peptide in the blood, a physician can monitor the success of the procedure.

•Monitor insulin production. A physician may order C-peptide tests to monitor insulin production over time and to determine if less insulin is being produced. In this case, a change in treatment may be recommended.

•Indicate Insulinoma. A high level of C-peptide in addition to a low blood glucose level may indicate a tumor of the pancreas, called an insulinoma, that results in the production of an excessive amount of insulin.

The function of C-peptide is unknown. However, researchers are exploring the possibility that C-peptide therapy may decrease a patient’s risk of certain diabetes complications by improving blood flow and nerve function. There is some recent research that suggests that C-peptide rather than being an inert byproduct of insulin synthesis is, in fact, important for preventing diabetic complications. This research is in its infancy.

If in fact it turns out that C-peptide is able to prevent complications, those of us who have secretory defects that respond to beta cell stimulation may have to reconsider whether or not to stimulate our beta cells with drugs like sulfonylureas or whether to supplement with injected insulin that does not contain C-peptide.

When the results of a C-peptide test indicate the presence of a disease or other medical disorder, a physician may initiate treatment for that condition.

A C-peptide test may be a very useful diagnostic tool in the initial period of diagnosis and at stages where a review of the medication is to be done. Its use during routine Type 2 medication may be limited but has its use when done, say once in 2-3 years and if the results are in the hands of a good doctor.

Lot of" if "s and " may"s, you may feel..... But that is how it is, as of today's science.