Home Testing Method has become very common today.

All those who know someone who has Diabetes will be aware of what a Glucometer or Blood-Glucose Meter (BCM) does.

This device allows you to check the glucose levels in your blood anytime, anywhere.

Perhaps, most of us are concerned with the blood glucose meter accuracy.

If we choose the one that costs the most, it must work the best, Right?

With countless Blood Glucose Meters (BCM) in the market, how do you know which one is the best for blood glucose testing?

You need to buy the one that is most durable, can do the job accurately and goes easy on your pocket.

In today’s article, we’ll talk about various factors that affect Blood Glucose Meter Accuracy.

Why Is The BCM Accuracy So Important?

If you have Diabetes, self-testing the blood sugar helps to manage the diet and treatment plan.

An accurate blood glucose reading helps to determine the right Insulin Dose. It helps to keep a check over the out-of-range blood sugar readings.

Inaccurate readings may result in Insulin dosing errors. It can lead to Hypoglycemia in some cases. It is a dangerous condition when the blood sugar level drops below 70mg/dL.

So, a glucometer needs to be accurate.

How Accurate Is Your Blood Glucose Meter?

Today, we have come far-off from the days when urine strips were used to check the glucose level in blood.

These strips only displayed a result when the glucose level was high enough to spill over into the urine.

But, the question is, how accurate are today’s blood glucose meters?

Fortunately, most glucometers are well designed and give precise readings. Though there are some things, you need to know about your glucometer and its accuracy.

Test Result Isn’t an Exact Measure

If you check your blood sugar twice or 3 times in a row, you may notice that you don’t get the same reading each time.

It doesn’t mean that your meter is not working correctly.

It does so due to the variance that is built into each meter.

Please note that if the glucometer results are within 15 per cent of the lab reading, they are considered accurate.

For example, if your glucometer result was 100mg/dL, it may vary to 85mg/dL on the downside or to 115mg/dL on the upside.

Glucometers Measure Blood Differently Than the Lab

All BCMs use whole blood measure the glucose level. Whereas, in a lab test, only the plasma portion of the blood is used to measure glucose. And, RBCs (red blood cells) are removed from the blood sample.

Glucometer test (whole blood glucose test) results are 12-15 per cent lower than the lab test (plasma glucose test).

Note: Though most of the BCMs measure the whole blood, newer meters automatically convert the results into plasma results.

What Factors Affect The Accuracy Of A Blood Glucose Meter?

Some of the factors that affect the accuracy of a meter are as under:

1. Extreme Temperature

Storing the test strips at high temperature or humidity can reduce the life span and affects the results.

Keep the glucose meter and test strips at room temperature (20 degrees C-25 degree C).

2. Test Strip Problems

Dispose of damaged and outdated test strips. Store the strips in a sealed container, away from heat, moisture and humidity.

Make sure that the strips are meant for a specific glucometer.

Don’t use the test strips of the expiry date.

3. Testing Site

Many of the modern glucose-meters provide the feature of Alternative Site Testing.

It is to be noted that blood sugar results aren’t as accurate if you test at places other than the fingertips (e.g., arm, leg, hand).

If your blood sugar level is rising and falling quickly, prefer the fingertip testing.

4. Monitor Problems

Insert the test strips completely into the monitor. And, replace the batteries of the monitor as needed.

5. Size And Quality Of The Blood Sample

If your red blood cells (RBCs) count is low or you are dehydrated, the results may be less accurate.

Once you apply the first drop to the test strip, avoid adding more blood to it.

6. Improper Coding

Some meters require to be coded to each container of the test strips. Match the code number of the device to the code number on the test strip container.

7. Dirt On The Skin

Wash the testing site and dry it properly before you prick the skin.

The tiniest amount of dirt, alcohol or other substances can affect the readings of the meter.

Tests To Control The Blood Glucose Meter Quality

You can perform the following quality control tests that can assure you that your meter is working correctly:

1. Using A Control Solution

Usually, these solutions come with your monitors.

Control solution contains a known level of glucose.

The solution is made to work with your meter and test strips to confirm the accuracy of the results.

It is advised to run the control tests monthly or whenever you purchase new strips.

To run this test, follow the same blood-testing procedure using this solution, instead of blood.

If the results fall in the accepted range, it means your meter and test strips are working properly.

2. Compare Your Meter Readings With Lab Results

It is the best way to check the accuracy of a meter.

Take your glucometer with you and check the blood sugar level immediately after you have a lab glucose test.

Then compare both the readings.

If the results fall within 15 per cent of the lab, they are considered accurate.

Important Points To Remember

  • Fingertip is the best site for checking blood sugar rather than other parts of the body. The reason is there are lots of capillaries close to the fingertips. Moreover, it’s an accessible area. So, it’s easy to draw enough percentage of blood for the test.
  • Make sure to read the instructions before using the strips. Don’t use the same strip twice for testing and dispose of them safely after use.
  • Every BGM is different. The amount of blood required for testing may vary from one meter to the other. Some require less, and some require a little more. You can read it out in the instructions.
  • Since each meter varies in terms of functioning, the battery change and charging requirements are unique to each device.
  • According to Medicare guidelines, one should clean and disinfect the glucometer after each use. One can clean the device by wiping it with soap and water using a cloth. You can also use Isopropyl alcohol.
  • If you find dried blood inside your meter, don’t run it under water. Instead, make a solution of soap and warm water. Take a cloth and wipe the blood off your meter.
  • Reusing the old/damaged or expired strips give error messages and may give false readings.
  • Two people can use the same meter to check their sugar levels. However, don’t share any sharp or lancing objects like needles with someone else for readings.
  • Close your control solution tightly and store it between 2C-30C. You can use this solution for three months after the first opening. After that, discard it.


A Blood Glucose Meter isn’t to be used for diagnosing diabetes.

It is to be used to keep a record of the blood sugar levels for managing diabetes.

If you have concerns about diabetes or if you feel that you may have diabetes, your doctor is the best person to test you for it.