How to diagnose Type 1 diabetes vs Type 2? Are there any special tests available for the diagnosis of Type 1 diabetes?
Diagnosis Of Type 1 Diabetes
The diagnosis of type 1 diabetes is primarily based on clinical features and elevated blood glucose levels. Patients with Type 1 diabetes typically have marked elevation in blood glucose level, which are usually more than 200 mg/dl at the time of diagnosis. These patients also experience dramatic symptoms due to marked elevation in blood glucose levels. These symptoms are: excessive thirst, excessive urination, weight loss, fatigue, and occasionally diabetic ketoacidosis (DKA.)
However, sometimes blood sugars may not be markedly elevated, especially in the early stages of Type 1 diabetes. Then, you may need one of the following blood tests to diagnose Type 1 diabetes.
Blood Tests To Diagnose Type 1 Diabetes
1. Fasting Blood Glucose To Diagnose Type 1 Diabetes
You go to laboratory after after you have fasted overnight. Usually it is part of a routine blood test such a metabolic panel.
A Fasting Blood Glucose greater than 125 mg/dl establishes the diagnosis of diabetes.
2. Hemoglobin A1c (HBA1C) For The Diagnosis of Type 1 Diabetes
Another blood test for the diagnosis of diabetes is Hemoglobin A1c – HbA1C . Hemoglobin A1 C above 6.5% clinches the diagnosis of diabetes.
Do You Have Type 1 Diabetes?
After the diagnosis of diabetes, the next important question is: what type of diabetes – Type 1 or Type 2.
Clinical Diagnosis of Type 1 Diabetes
You Are Probably a Type 1 Diabetic If:
- You have been on insulin ever since the diagnosis of your diabetes or shortly thereafter (although sometimes your physician may erroneously place you on insulin even though you are a Type 2 diabetic)
- On relatively small doses of insulin (usually less than 40 units/day)
- Not overweight
- No family history of diabetes
- You do not have high triglycerides and low HDL cholesterol
- Your blood pressure is normal.
How to Diagnose Type 1 Diabetes Vs Type 2
There is a special blood test that can help to diagnose Type 1 diabetes vs Type 2. This blood test is known as C-peptide. What is C-peptide? It is a hormone that the pancreas produces in conjunction with insulin.
The blood test for C-peptide should be done one hour after a meal.
Almost all Type 2 diabetic patients have some production of insulin and C-peptide. Actually, many Type 2 diabetics have excessive production of insulin and an elevated level of C-peptide. In contrast, most Type 1 diabetics have no insulin production and, therefore, no C-peptide in their blood.
Rarely, C-peptide is detectable in the early stages of Type 1 diabetes but in small quantities. In these difficult cases, your endocrinologist will likely order further blood testing, such as anti-islet cell antibodies or anti-GAD antibodies. These antibodies are present in most Type 1 diabetic patients.
Honeymoon period In Type 1 Diabetes
In some Type 1 diabetic patients, initial high blood sugars normalize spontaneously. Then, a patient goes through a period of normal blood sugars which can last several months (even years.) This is referred to as the honeymoon period. Afterwards, there is a gradual increase in the blood sugar levels, back into the diabetic range.
Diagnosing Type 1 Diabetes In Adults
Type 1 diabetes typically starts in childhood or teenage. That’s why we used to call it Juvenile-Onset diabetes as compared to Maturity-Onset diabetes (Type 2 diabetes.) However, Type 1 diabetes can rarely start in your adult life. That’s why we no longer use the old terminologies like Juvenile-Onset diabetes or Young-Onset diabetes.
Obviously, it can be challenging to diagnose Type 1 diabetes in adults for a physician who is stick in the old terminology. But a physician who is not stuck in the outdated terminologies, can easily diagnose Type 1 diabetes in adults using the same guideline as outlined earlier.
Diagnosing Type 1 diabetes is often straightforward. However, occasionally it may be challenging. Then, an endocrinologist can do the appropriate testing to distinguish between Type 1 diabetes vs. Type 2.