Testing and Monitoring Diabetes at Home

Type 2 diabetes is caused by excessively high blood glucose (sugar) levels. Glucose provides energy to cells throughout the body. Insulin, a hormone produced by the pancreas, helps glucose enter cells. Type 2 diabetes occurs when your body no longer responds to insulin appropriately (insulin resistance) or doesn't make enough insulin. Checking blood sugar levels at home is vital for managing diabetes and helping to prevent diabetic complications.

This article discusses how to check your blood sugar at home, interpret your results, and why this is an important habit when you have type 2 diabetes.

Person taking sample for blood glucose test for type 2 diabetes

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Diagnosing Diabetes

Type 2 diabetes is diagnosed through blood tests, such as:

  • A1C levels (average blood sugar levels over two to three months)
  • Fasting blood sugar test (blood sugar levels measured after fasting overnight)
  • Glucose tolerance test (blood sugar levels taken before and after drinking a sugary drink)
  • Random blood sugar test (blood sugar levels taken at any time)

Monitoring Blood Sugar With Diabetes

Monitoring blood sugar is vital for helping to prevent serious health conditions that can develop from type 2 diabetes, such as:

Who Should Check Blood Sugar at Home?

If you've been diagnosed with type 2 diabetes, you should monitor your blood sugar several times each day at home.

Types of Blood Sugar Tests

Blood sugar levels can be checked intermittently with prick tests (using your finger, or other areas of the body) or with continuous glucose monitoring.

Prick Test

Blood glucose levels are commonly measured with a device called a glucometer using a few drops of blood—typically obtained by pricking a fingertip. However, other sites can be pricked, including the thigh, calf, forearm, palm, or upper arm.

A tiny needle called a lancet is used to pierce the skin. A small amount of blood is placed on a test strip and inserted into the glucometer. The device then displays your current blood sugar levels in milligrams of glucose per deciliter of blood (mg/dl).

Continuous Glucose Monitoring

Continuous glucose monitoring (CGM) is achieved through a small sensor implanted just under the skin—typically in the upper arm or belly. This device measures glucose levels in fluid between your cells every few minutes, 24 hours per day. This information is sent to your phone or a separate device, such as an insulin pump.

Continuous glucose monitoring devices can alarm you when blood sugar levels are too high or too low, which can help you avoid an emergency. However, these devices are expensive, and results still need to be confirmed twice daily with a traditional finger prick test.

Symptoms of Type 2 Diabetes

If you have symptoms of type 2 diabetes, talk to your healthcare provider. These can include:

How to Test Your Blood Sugar

Although there are general guidelines for how and when to test your blood sugar, you should always follow the specific instructions given by your healthcare provider.

When to Test Blood Sugar

Blood sugar can be checked anytime, especially if you feel like it might be too high or too low. However, in general, blood sugar levels should be checked:

  • First thing in the morning, before eating or drinking
  • Prior to each meal
  • Two hours after you eat
  • Before you go to bed

It's also a good idea to check your blood sugar before and after exercise.

Tips for Getting Accurate Results

Many factors can affect the accuracy of your blood sugar test results, such as:

  • Following test instructions properly
  • Quality of testing products
  • Environmental factors (temperature, altitude, humidity)
  • How you store testing supplies
  • Certain substances in your system, such as Tylenol (acetaminophen), vitamin C, or uric acid
  • How hydrated you are
  • Iron levels

Be sure to follow your testing instructions closely and dispose of testing products that are expired or not working properly.

Other Testing Options

In addition to blood tests, blood glucose levels can be tested using urine or cerebrospinal fluid samples.

Understanding Results of Blood Sugar Testing

Your healthcare provider will determine your specific blood glucose target levels. However, in general, blood sugar should be between 80 and 130 mg/dL before a meal and less than 180 mg/dL two hours after you eat.

Low blood sugar (hypoglycemia) occurs when blood sugar levels are below 70 mg/dL. Severe hypoglycemia—below 54 mg/dL—can lead to a life-threatening emergency.

Symptoms of hypoglycemia can include:

  • Racing heartbeat
  • Sweating
  • Feeling nervous or anxious
  • Increased appetite
  • Confusion
  • Mood swings
  • Dizziness

Symptoms of severe hypoglycemia require immediate medical attention. These include:

  • Significant weakness
  • Severe confusion
  • Difficulty walking
  • Seizures

Once low blood sugar is detected, sugar is consumed to raise levels back to normal, often from juice, candy, soda, or glucose tablets.

Blood sugar levels can also be too high, causing hyperglycemia (high levels of calcium in the blood). Levels higher than 240 mg/dL can lead to diabetic ketoacidosis (DKA), a medical emergency. This condition can lead to coma or even death.

Symptoms of hyperglycemia can include:

  • Dry skin or mouth
  • Headache or stomach pain
  • Breath that smells "fruity"
  • Flushed face
  • Increased thirst and/or urination
  • Deep breathing at a fast pace
  • Muscle pain or stiffness
  • Nausea or vomiting

Hyperglycemia is often treated with an insulin injection.

Summary

Type 2 diabetes is a condition that affects your body's ability to properly manage blood glucose levels. Blood sugar levels need to be tested several times per day to ensure they stay within a healthy range—generally between 80 and 130 mg/dL before meals and less than 180 mg/dL two hours after eating. Your healthcare provider will dictate exact instructions for the frequency of testing.

Blood glucose levels are most commonly tested with a finger prick test using a glucometer. However, continuous glucose monitoring devices can also be used.

A Word From Verywell

Type 2 diabetes is a condition that can lead to serious health problems if you don't properly manage your blood sugar levels. Always follow your healthcare provider's instructions for testing and treating your condition.

Frequently Asked Questions

  • Are home diabetes tests accurate?

    Many factors can affect the accuracy of blood glucose tests at home. You can reduce your risk of inaccurate results by following the testing instructions precisely and making sure your testing equipment is in good working order. You can double-check blood sugar levels obtained from continuous glucose monitoring devices with a prick test.

  • What are signs that your blood sugar needs to be tested?

    Symptoms that suggest your blood sugar levels might be out of normal range can include increased heartbeat, sweating, confusion, weakness, headache, nausea, vomiting, dry mouth or skin, flushed face, increased urination, increased thirst, dizziness, difficulty walking, and seizures.

  • When is the best time to check blood sugar?

    Blood sugar levels should be checked based on the specific schedule given by your healthcare provider. In general, blood sugar should be checked first thing in the morning, before meals, two hours after meals, before and after exercise, and before bed. You should also check your blood sugar any time you notice signs that it might be out of range.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Institute of Diabetes and Digestive and Kidney Diseases. Type 2 diabetes.

  2. Centers for Disease Control and Prevention. Diabetes tests.

  3. U.S. Food and Drug Administration. Blood glucose monitoring devices.

  4. National Institute of Diabetes and Digestive and Kidney Diseases. Continuous glucose monitoring.

  5. Centers for Disease Control and Prevention. Manage blood sugar.

  6. U.S. National Library of Medicine. Glucose urine test.

  7. Centers for Disease Control and Prevention. Low blood sugar (hypoglycemia).

By Aubrey Bailey, PT, DPT, CHT
Aubrey Bailey is a physical therapist and professor of anatomy and physiology with over a decade of experience providing in-person and online education for medical personnel and the general public, specializing in the areas of orthopedic injury, neurologic diseases, developmental disorders, and healthy living.