Testing your blood sugar at home takes about 30 seconds once you have the right supplies and know the steps. The process involves pricking your finger with a tiny needle, placing a drop of blood on a test strip, and reading the result on a small handheld meter. There’s also a newer option, continuous glucose monitors, that track your levels automatically throughout the day.
What You Need
A basic blood sugar testing kit has four components. The glucose meter is a small handheld device that reads the chemical reaction on a test strip and displays your blood sugar as a number in mg/dL. Test strips contain enzymes that react with glucose in your blood to produce an electrical signal the meter translates into a reading. Strips must match your specific meter model.
Lancets are tiny, single-use needles that prick the skin. They load into a lancing device, a spring-loaded pen that controls how deep the needle goes and how fast it fires. Most lancing devices have adjustable depth settings, which matter more than you might think for both comfort and accuracy.
You can buy complete kits at any pharmacy, and many insurance plans cover the supplies. Test strips are the ongoing cost, so check what your plan covers before choosing a meter.
Step-by-Step Testing Process
The CDC recommends this sequence:
- Make sure your meter is charged and ready.
- Wash your hands with soap and warm water, then dry them thoroughly. Don’t use hand sanitizer, as residue on your skin can throw off the reading.
- Massage or shake out your hand to push blood into your fingertips.
- Load a fresh lancet into your lancing device and prick the side of your fingertip (not the pad, which has more nerve endings).
- Squeeze gently from the base of the finger to form a round drop of blood.
- Touch the drop to the test strip. Don’t try to add more blood after the first application.
- Insert the strip into the meter if you haven’t already (some meters require you to insert the strip first).
- Your reading appears within a few seconds.
Making It Less Painful
Pain from lancing depends almost entirely on how deep the needle goes. Research published in the Journal of Diabetes Science and Technology confirmed that both blood volume and pain increase significantly at higher depth settings. A lancet needs to reach the tiny blood vessels just under your skin’s surface, but going deeper increases the chance of hitting nerve fibers beneath them.
Start at the lowest depth setting on your device and work up only if you can’t get enough blood. The ideal setting varies not just from person to person but from finger to finger, so experiment. Always prick the lateral (side) surface of the fingertip rather than the center pad, and apply gentle pressure along the finger after the prick to coax out the drop.
When to Test
Your testing schedule depends on your type of diabetes and treatment plan. People with type 1 diabetes typically need to test before meals and snacks, before and after exercise, at bedtime, and sometimes during the night. If you take multiple daily insulin injections for type 2 diabetes, testing before meals and at bedtime is common. If you use a long-acting insulin, you may only need to check before breakfast and occasionally before dinner.
Regardless of type, you should test more frequently when you’re sick, changing your eating or exercise habits, starting a new medication, or driving long distances.
Understanding Your Numbers
The American Diabetes Association recommends these targets for most nonpregnant adults with diabetes:
- Before a meal (fasting): 80 to 130 mg/dL
- One to two hours after starting a meal: less than 180 mg/dL
Your personal targets may differ based on your age, how long you’ve had diabetes, and other health conditions. The pre-meal number tells you your baseline. The post-meal number tells you how your body handled the food you ate. Tracking both over time reveals patterns that help you and your care team adjust your plan.
What Can Throw Off a Reading
Home meters are reliable, but several factors can skew results. According to the Mayo Clinic, the most common culprits are:
- Damaged or expired test strips. Store strips in their sealed container, away from moisture. Never use strips past their expiration date.
- Dirty hands. Food residue, lotion, or even fruit juice on your fingers can artificially raise a reading. Soap and water is the gold standard for cleaning before a test.
- Temperature extremes. Keep your meter and strips at room temperature. Leaving them in a hot car or cold garage affects accuracy.
- Too little blood on the strip. A small or smeared sample gives unreliable results. You need a full, round drop.
- Dehydration or anemia. Changes in your red blood cell concentration can make readings less accurate.
If a result seems off, wash your hands again and retest with a fresh strip before making any treatment decisions.
Testing on Sites Other Than Your Fingertip
Some meters allow you to test on your forearm, thigh, or palm. These alternate sites hurt less because they have fewer nerve endings. But there’s a tradeoff: forearm and thigh readings are only reliable when your blood sugar is stable, such as before meals. When levels are rising or falling quickly (after eating, after exercise, or during a low), these sites lag behind what’s actually happening in your bloodstream.
The palm is the exception. Research shows palm testing matches fingertip accuracy at all times, including after meals and exercise. The success rate for alternate sites is also slightly lower (about 94.5% versus 98.3% for fingertips), which means more wasted strips over time. If you get a suspicious reading from an alternate site, confirm it with a fingertip test.
Continuous Glucose Monitors
A continuous glucose monitor, or CGM, is a small sensor you wear on your body that measures glucose levels automatically every few minutes. Instead of pricking your finger, the sensor sits just under the skin and reads glucose in the fluid between your cells. You check your levels on a smartphone app or a dedicated receiver.
Applying a CGM sensor takes about a minute. For the Dexcom G7, one of the most common models, you clean the site with an alcohol wipe, let it dry for at least 10 seconds, press the applicator against your skin, and push a button. A thin filament inserts painlessly under the skin, and an adhesive patch holds it in place. Most adults wear the sensor on the back of the upper arm. An overpatch goes on top to keep it secure during showers, exercise, and sleep.
CGMs are especially useful if you need to test frequently, have trouble recognizing low blood sugar, or want to see how specific foods and activities affect your levels in real time. They don’t eliminate finger pricks entirely for everyone, but they reduce them dramatically.
Disposing of Lancets Safely
Used lancets are considered sharps and should never go directly into your household trash. The FDA recommends placing each used lancet into a sharps disposal container immediately after use. You can buy one at a pharmacy, or use a heavy-duty plastic container like a laundry detergent bottle with a screw-on lid.
When the container is about three-quarters full, seal it and dispose of it through your community’s sharps program. Options vary by location but include drop-off boxes at pharmacies, hospitals, or fire stations; household hazardous waste collection sites; and mail-back programs. For disposal options specific to your state, you can call Safe Needle Disposal at 1-800-643-1643. Keep sharps containers out of reach of children and pets, and never reuse or overfill them.