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.
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:
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)
Loss of vision Nerve damage (peripheral neuropathy) Foot ulcers/wounds Gum disease/dental issues Kidney and/or heart disease Stroke Sexual dysfunction Bladder issues Sleep apnea (sleep disorder in which you repeatedly start and stop breathing) Certain types of cancer Dementia Depression
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.
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.
Excessive thirst Frequent urination Fatigue Tingling or numbness in hands or feet Unexplained weight loss Wounds that have trouble healing Blurry vision Increased hunger
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 drinkingPrior to each mealTwo hours after you eatBefore 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 properlyQuality of testing productsEnvironmental factors (temperature, altitude, humidity)How you store testing suppliesCertain substances in your system, such as Tylenol (acetaminophen), vitamin C, or uric acidHow hydrated you areIron levels
Be sure to follow your testing instructions closely and dispose of testing products that are expired or not working properly.
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 heartbeatSweatingFeeling nervous or anxiousIncreased appetiteConfusionMood swingsDizziness
Symptoms of severe hypoglycemia require immediate medical attention. These include:
Significant weaknessSevere confusionDifficulty walkingSeizures
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 mouthHeadache or stomach painBreath that smells “fruity"Flushed faceIncreased thirst and/or urinationDeep breathing at a fast paceMuscle pain or stiffnessNausea 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.
