Are We Diagnosing Diabetes Too Late?

As a physician, I often ask myself, "Are we diagnosing type 2 diabetes too late?" The traditional methods of diagnosis rely heavily on hemoglobin A1c, a lab test that provides the average blood sugar level over the last three months. This test is useful, but it may not tell the whole story when it comes to identifying insulin resistance or pre-diabetes early enough. Let’s explore why this might be the case and what steps you can take to stay ahead of diabetes.

The Role of Hemoglobin A1c and Blood Sugar in Diagnosing Diabetes

Type 2 diabetes is typically diagnosed using a hemoglobin A1c test. This test is often drawn during annual visits with your primary care doctor and tells us how well your blood sugar has been controlled over the past three months. A normal hemoglobin A1c is below 5.7%. Pre-diabetes, where the body is already struggling with insulin resistance, is diagnosed with an A1c between 5.7% and 6.4%. A diagnosis of diabetes happens when the A1c reaches 6.5% or higher.

But there’s a catch. In many cases, doctors still rely on a one-time fasting blood sugar test rather than an A1c. A fasting blood sugar below 100 mg/dL is considered normal, and levels above 126 mg/dL indicate diabetes. The problem? Fasting blood sugar tests alone can miss signs of pre-diabetes and early insulin resistance. And even if your doctor does get a hemoglobin A1c it too can often be normal in patients with early insulin resistance - leading to a missed opportunity for early intervention.

The Importance of Identifying Insulin Resistance Early

Insulin resistance is an early stage of metabolic dysfunction where the body’s cells don’t respond well to insulin, the hormone responsible for moving sugar from the bloodstream into the cells. In insulin resistance, the pancreas has to work overtime to produce more insulin to maintain normal blood sugar levels. The catch here is that while the blood sugar may remain in the normal range, the body is compensating by secreting more insulin.

For example, let’s look at two patients:

- Patient A has a fasting blood sugar of 85 mg/dL and is using very little insulin—say, 2 units—to maintain that level. This patient’s metabolism is functioning well.

- Patient B, also with a fasting blood sugar of 85 mg/dL, is using 20 units of insulin to maintain that same level. In this case, the pancreas is working much harder to keep blood sugar under control. While the blood sugar may appear normal, this patient is dealing with significant insulin resistance.

These two patients are not the same. Patient B may experience trouble losing weight, fatigue, fatty liver, elevated cholesterol, and even symptoms of polycystic ovarian syndrome (PCOS)—all signs of insulin resistance. But because the fasting blood sugar and hemoglobin A1c are normal, these issues are often overlooked.

The Problem With Pre-Diabetes and the Opportunity for Early Intervention

Even in the pre-diabetes stage, many patients have already developed significant metabolic problems, including insulin resistance. Pre-diabetes is a warning sign that your body is struggling to manage blood sugar effectively. Left unchecked, it can progress to full-blown diabetes, along with an increased risk of heart disease and stroke.

But here’s the critical point: even before a diagnosis of pre-diabetes, we can take action. Lifestyle changes—such as increasing exercise, improving diet, managing stress, and optimizing sleep—can dramatically improve insulin sensitivity and reduce the risk of progressing to diabetes.

How to Catch Insulin Resistance Early: The Fasting Insulin Test

Unfortunately, the traditional approach of relying on fasting blood sugar and hemoglobin A1c doesn’t catch insulin resistance early enough. To truly understand whether you’re at risk, I recommend asking your doctor to check your fasting insulin level along with your fasting blood sugar.

There’s a helpful formula called HOMA-IR (Homeostatic Model Assessment of Insulin Resistance) that you can use to assess your level of insulin resistance. The formula is simple: multiply your fasting blood sugar by your fasting insulin level, then divide by 405. If the result is over 2, there’s a strong likelihood that you have some level of insulin resistance.

The Bottom Line: Don’t Wait for the Diagnosis of Diabetes to Act

In my experience, waiting for a diagnosis of type 2 diabetes is too late. If you suspect you may have insulin resistance—whether it’s due to trouble losing weight, a diagnosis of PCOS, or even just a family history of diabetes—it’s essential to act now. Ask your doctor about a fasting insulin test, calculate your HOMA-IR score, and start making changes to your lifestyle today.

The earlier we intervene, the better our chances of reducing your risk of diabetes, heart disease, and stroke later in life. Don’t wait for the diagnosis—let’s get ahead of it together.