Which Test Answers Which Question

A fingerstick meter gives you one reading. It shows your blood sugar at the moment you test.

A continuous glucose monitor, or CGM, is a sensor worn on the skin. It reads glucose about every 1 to 5 minutes. So you see a line of readings over hours and days.

Your care team can tell you how often to check.

A cut-away of skin shows a round sensor on top with a thin wire reaching into the fluid between the cells, and a blood vessel with sugar cubes below. Beside it, a reader screen draws a line of readings. Sugar cubes move from the blood into the fluid by the wire. On the screen, the sensor line trails the blood line by a little, and last a blood drop marks one finger check as a single dot on the line.

The lab A1C is a simple blood draw. No fasting is needed.

It reflects roughly the past two to three months. Think of it as a report card for that stretch.

It is a percentage, not a meter reading. Each test answers a different question, so doctors often use them together. Knowing which test a number came from keeps you comparing like with like.

Three calendar pages fill with meter check dots, most green and a few amber for high readings. The dots flow into one jar labeled A1C, which fills to a single average level. One high dot is circled while the A1C level stays steady.

Key takeaways

• A fingerstick meter shows one moment.
• A CGM sensor shows a line of readings over hours and days.
• A lab A1C reflects roughly the past two to three months.

Try it

Write down which test each of your next three numbers came from, then bring that list to your next visit.