Checking your blood sugar at home
Home blood glucose testing is done with a finger-prick meter, and its value depends entirely on when you test. Fasting readings show whether your background medicine is right; readings two hours after a meal show how that meal affected you. For most non-pregnant adults the targets are 80–130 mg/dL fasting and under 180 mg/dL two hours after eating. People on insulin need to test more often than those on tablets alone, and a well-kept logbook of a few purposeful readings is worth far more than dozens of random ones.
Diabetologist & General Physician · MBBS
A glucometer answers a narrow question very well: what is the glucose in this drop of blood, right now. It cannot tell you what your average has been — that is what HbA1c is for — and it cannot tell you anything useful if the readings are taken at random times with no record kept.
Targets for most adults
| When | Target (mg/dL) | Target (mmol/L) |
|---|---|---|
| Fasting / before meals | 80 – 130 | 4.4 – 7.2 |
| 2 hours after a meal | Below 180 | Below 10.0 |
| Before bed | 100 – 140 | 5.6 – 7.8 |
How to test properly
- Wash hands with soap and warm water and dry them. Do not use spirit — residue on the skin alters the reading, and traces of fruit or sweet tea on a finger can produce a spectacularly false high.
- Insert the strip and check the meter has coded to the right batch.
- Prick the side of the fingertip, not the pad — the sides hurt less and have as good a blood supply.
- Let a drop form on its own. Squeezing hard pushes tissue fluid out with the blood and dilutes the sample.
- Touch the strip to the drop and wait for the reading.
- Write it down with the time and what you had eaten.
When to test
Testing to a plan turns a meter into information. Testing at random turns it into anxiety.
| Your treatment | Reasonable pattern |
|---|---|
| Diet alone or metformin only, stable | A few times a week, varying the time of day |
| Sulfonylurea (gliclazide, glimepiride) | Fasting most days, plus any time you feel unwell |
| Basal insulin once daily | Fasting daily — that is the reading the dose is set by |
| Multiple daily insulin injections | Before each meal and at bedtime |
| Unwell, fasting in Ramadan, or changing dose | More often, including mid-afternoon |
Paired testing: the trick worth learning
Test immediately before a meal and again two hours after the first bite. The difference between the two numbers is what that meal did to you — not what food charts say it should do. Two rotis with dal may raise one person by 40 mg/dL and another by 90. Paired testing on a handful of your usual meals teaches you more about your own diet in two weeks than a year of general advice.
Readings that need action
Continuous glucose monitors
A CGM is a small sensor worn on the arm or abdomen that reads glucose every few minutes and shows the direction of travel, not just the level. It is genuinely better information, especially for anyone on insulin or with hypo unawareness. In Pakistan the recurring sensor cost is the obstacle, and nobody reimburses it. A glucometer used with a plan remains good care, and it is worth saying plainly: you are not managing your diabetes badly because you use finger-pricks.
Looking after the meter
- Keep strips in their original tube with the lid closed — they spoil with humidity, which matters in a Gujrat summer.
- Check the expiry date on the strip pot; expired strips read inaccurately, not obviously wrongly.
- Do not leave the meter in a car or in direct sun.
- Bring the meter to your appointments so the stored readings can be reviewed alongside your HbA1c.
Common questions
Still not sure what to do?
Reading about a symptom only goes so far. A doctor who can ask you questions and examine you will get further in ten minutes than any article can.
