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Testing at home

A finger-prick meter lets you check your blood sugar yourself, at home and on the go. Here is how to take a reading, how often to do it, and how to make sure the number is accurate.

What you need

A home blood glucose test uses three things: a meter, a single-use test strip, and a lancet in a finger-pricking device. In the UK, meters give the result in millimoles per litre (mmol/L). Your diabetes team or pharmacist can help you choose a meter and show you how it works with your strips.

How to take a reading

  1. Wash your hands in warm water and dry them well. Warm hands bleed more easily, and food or fruit juice left on your fingers can give a falsely high result.
  2. Put a test strip into the meter.
  3. Prick the side of a fingertip with the lancet – it is less painful than the fleshy pad.
  4. Gently squeeze out a drop of blood and touch it to the strip.
  5. Wait a few seconds for the meter to show your reading.
  6. Write it down, or log it in the app so you can see the pattern later.

Rotate which finger you use so one spot does not get sore. Never share a lancet or finger-pricker with anyone else – it carries a risk of passing on infection.

How often should you test?

This depends on your type of diabetes and your treatment, and your diabetes team will advise you. As a general guide:

  • Type 1: most people are advised to test at least four times a day – before meals and before bed – and more often around driving, exercise or illness.
  • Type 2 on insulin or hypo-causing medicines: your team will tell you when and how often to test.
  • Type 2 not on those medicines: you do not usually need to test yourself routinely.

Testing is individual

There is no single rule that fits everyone. How often you test, and the times of day that matter most, are agreed with your diabetes team – always follow their advice over any general guide, including this one.

Continuous glucose monitors and flash sensors

A continuous glucose monitor (CGM) or flash sensor is worn on the skin and reads your glucose through the day, so you can see it without a finger-prick each time. Many people with type 1 – and some with type 2 – now get one on the NHS.

These sensors measure glucose in the fluid just under the skin, so they can lag a little behind a finger-prick. A finger-prick is still used to confirm a hypo, or whenever a sensor reading does not match how you actually feel.

Getting an accurate result

  • Use in-date strips and store them as the packaging says.
  • Make sure the meter is set up for the strips you are using.
  • Apply enough blood to the strip – a half-filled strip can read wrong.
  • Clean and dry your hands first, so nothing on your skin skews the number.

A reading below 4

A result under 4.0 mmol/L is a hypo and needs treating straight away. If a reading looks very low or very high but you feel fine, wash your hands and test again before acting. See what to do about a hypo or a very high reading.

Why keep a record

The pattern over time matters far more than any single reading – it is the trend, not one number, that guides changes to your treatment. Logging your results lets you and your team see which times of day run high and whether a change is working. You can start logging free, share a report with your GP or nurse, and read what the numbers mean.

Checked against NHS and NICE guidance on . See all official sources.