How to Know if you have Diabetes

Table of Contents

Person checking blood sugar at home using a glucose meter — Regular monitoring helps detect diabetes early before major complications begin.

By Adam | Published November 13, 2025

Quick answer: Persistent thirst, frequent urination, unexplained fatigue, blurred vision, and slow-healing wounds indicate elevated blood glucose. Confirm diagnosis with fasting blood glucose, A1C, or oral glucose tolerance tests.

Quick summary

Symptoms: excessive thirst, frequent urination, blurred vision, slow wound healing.
Tests: fasting glucose, A1C, and oral glucose tolerance test.
Risk groups: overweight adults, family history, gestational diabetes history.

Introduction: The silent condition that changes metabolism

Diabetes develops gradually and damages blood vessels and nerves before symptoms become obvious. Hundreds of millions live with diabetes, often undiagnosed. This guide explains what to watch for, which tests confirm the diagnosis, and the steps that protect your organs and lifespan.

Infographic explaining how insulin regulates blood glucose in the body — Infographic: How insulin regulates blood glucose and what happens when regulation fails.

Understanding diabetes: the basic pathology

Diabetes is a chronic metabolic disorder where insulin fails to regulate blood glucose. The body either produces too little insulin or cannot use it efficiently, leading to persistent hyperglycemia and organ damage.

Types of diabetes

Type 1: Autoimmune destruction of insulin-producing cells; requires lifelong insulin therapy.
Type 2: Insulin resistance combined with relative insulin deficiency; associated with obesity and inactivity.

Primary warning signs you must not ignore

Infographic showing major warning signs of diabetes including thirst, urination, fatigue, and blurry vision — Infographic: Key warning signs of diabetes every adult should recognize.

Excessive thirst and frequent urination

High blood glucose draws fluid from tissues, triggering dehydration and constant thirst. Nighttime urination is often the first physical sign of dysregulated glucose.

Unexplained fatigue

When glucose cannot enter cells, energy production drops. Persistent exhaustion even after rest indicates glucose imbalance.

Slow wound healing

Elevated glucose damages blood vessels, slowing oxygen delivery to tissues. Even small cuts can take weeks to heal—a clear red flag that glucose levels are uncontrolled.

Blurred vision and numbness

Fluctuating glucose disturbs eye focus and damages peripheral nerves, leading to vision changes and tingling in the extremities.

How clinicians confirm the diagnosis

Chart comparing diabetes diagnostic tests: fasting glucose, A1C, oral tolerance test — Clinical comparison of key diagnostic tests for diabetes confirmation.

Test	Normal	Prediabetes	Diabetes
Fasting Blood Glucose	<100 mg/dL	100–125	≥126 on 2 occasions
A1C	<5.7%	5.7–6.4%	≥6.5%
OGTT (2-hour)	<140 mg/dL	140–199	≥200

Who should get tested and how often

Adults aged 40+
People with obesity or family history
History of gestational diabetes
High blood pressure or cholesterol

Prediabetes is reversible

People exercising and preparing balanced meals to prevent diabetes — Lifestyle changes including balanced nutrition and regular exercise can reverse prediabetes.

Lose 5–10% of body weight.
Exercise 30 minutes daily.
Limit refined sugars and processed carbs.
Prioritize 7–8 hours of sleep and stress control.

Real patient example

Portrait of woman who improved diabetes control with lifestyle changes — Case study: Maria reduced her A1C from 9.2% to 6.1% within six months through medical and lifestyle intervention.

Maria, 42, ignored early symptoms until testing confirmed diabetes. Within six months of structured nutrition and medication, she regained metabolic control and prevented further complications.

Complications of untreated diabetes

Without intervention, hyperglycemia leads to cardiovascular disease, kidney failure, and neuropathy. Early control prevents irreversible organ damage.