You can check your glucose levels at home using a handheld blood glucose meter (glucometer) or a continuous glucose monitor worn on your body. Most people start with a glucometer, which involves pricking a fingertip and placing a drop of blood on a test strip. The whole process takes under a minute once you get the hang of it.
Using a Blood Glucose Meter
A glucometer kit includes the meter itself, a lancing device (a spring-loaded tool that holds a small needle), test strips, and a logbook or app for tracking. Here’s the step-by-step process:
- Prepare the meter. Make sure it’s charged and has a fresh test strip inserted, or have one ready.
- Wash your hands. Use soap and warm water, then dry thoroughly. Residue from food, lotion, or hand sanitizer can throw off your reading. Don’t substitute alcohol wipes unless you let the site dry completely before pricking.
- Get blood flowing. Massage or shake out the hand you’ll prick. This helps a good drop of blood form quickly so you don’t have to squeeze hard.
- Prick the side of your fingertip. Use the lancing device on the side of your finger rather than the pad. It hurts less and still produces a reliable drop.
- Apply blood to the strip. Squeeze gently from the base of your finger and touch a generous drop to the test strip. Don’t try to add more blood after the first drop is applied, as this can cause an inaccurate reading.
- Read and record your result. The meter displays your blood sugar in a few seconds. Log it along with the time, what you ate recently, and anything else that might explain the number (exercise, stress, illness).
- Dispose of the lancet and strip. Drop both into a trash container. Replace the lancet regularly so it stays sharp and causes less pain.
Testing From Sites Other Than Your Fingertip
Some meters allow you to draw blood from your forearm, the base of your thumb, your upper arm, or your thigh. This can be a welcome option if your fingertips are sore from frequent testing. However, these alternative sites are less accurate when your glucose is changing rapidly, such as right after a meal, after taking insulin, during exercise, or when you’re sick or stressed.
Stick with fingertip testing if you suspect your blood sugar is low, if you don’t typically feel symptoms when it drops, or if an alternative-site reading doesn’t match how you feel. Not every meter supports alternative sites, so check your device’s instructions before trying.
Continuous Glucose Monitors
A continuous glucose monitor, or CGM, tracks your glucose around the clock without fingersticks. It uses a tiny sensor inserted just beneath your skin (usually on your upper arm or abdomen) that measures glucose in the fluid between your cells. A transmitter sends readings wirelessly to your phone or a small receiver, giving you a real-time number and a graph of your trend over hours or days.
Because CGMs read interstitial fluid rather than blood directly, there’s a slight lag of a few minutes compared to a fingerstick reading. This matters most when glucose is rising or falling fast. CGMs are especially useful for spotting overnight lows and post-meal spikes you’d otherwise miss with periodic finger pricks.
What the Numbers Mean
For adults with diabetes, the American Diabetes Association recommends a pre-meal glucose of 80 to 130 mg/dL and a reading below 180 mg/dL one to two hours after the start of a meal. These targets apply to most nonpregnant adults, though your provider may set a tighter or looser range based on your situation.
Blood sugar below 70 mg/dL is considered low (hypoglycemia). Early symptoms include a fast heartbeat, shaking, sweating, dizziness, sudden hunger, and feeling anxious or irritable. Below 54 mg/dL is severe low blood sugar, which can cause confusion, trouble walking or seeing clearly, weakness, and even seizures or loss of consciousness. If your meter shows a number in that range, treat it immediately with fast-acting sugar like juice or glucose tablets.
When and How Often to Test
Testing frequency depends on your type of diabetes and treatment plan. People taking insulin often need to check several times a day: first thing in the morning (fasting), before meals, one to two hours after meals, and at bedtime. Those managing type 2 diabetes without insulin may test less frequently, sometimes just a fasting reading and one post-meal check. Your provider will help you build a schedule that fits your treatment.
A single fingerstick captures only one moment in time. That’s why patterns matter more than any individual reading. Logging your results consistently, along with context like meals and activity, turns scattered data points into a picture your provider can use to adjust your plan.
Lab Tests for Glucose
Home monitoring gives you day-to-day numbers, but lab tests offer a bigger-picture view. The two most common are the A1C test and the oral glucose tolerance test.
A1C Test
The A1C measures your average blood sugar over roughly the past two to three months. It’s reported as a percentage. Below 5.7% is normal. Between 5.7% and 6.4% falls in the prediabetes range. A result of 6.5% or above indicates diabetes. Unlike a fingerstick, a single high or low day doesn’t move your A1C much, making it a reliable gauge of overall control.
Oral Glucose Tolerance Test
For this test you fast overnight, then drink a sugary solution containing 75 grams of glucose. Your blood is drawn two hours later. A reading below 140 mg/dL is normal. Between 140 and 199 mg/dL suggests prediabetes. A result of 200 mg/dL or higher points to diabetes. Pregnant individuals may undergo a longer version of this test with a 100-gram glucose load and blood draws at one, two, and three hours.
Factors That Throw Off Your Reading
Even with good technique, certain conditions can skew a home meter’s accuracy. Temperature extremes are a common culprit: store your meter and test strips at room temperature, and avoid leaving them in a hot car or cold garage. Expired or damaged test strips also produce unreliable results, so check the date on the vial and keep it sealed against moisture.
Dehydration and anemia (a low red blood cell count) both affect how glucose meters calculate your reading. If you’ve been sick or haven’t been drinking enough fluids, your numbers may read higher than expected. Applying too little blood to the strip is another frequent source of error. Let a full, round drop form before touching it to the strip, and resist the urge to smear or add a second drop.
If a reading seems off, or doesn’t match how you feel, the simplest fix is to wash your hands again, use a fresh strip, and retest from your fingertip. Consistent results across two tests give you much more confidence than a single surprising number.