Blood Glucose 8 tested - mmol/L or mg/dL?

Most meters outside the US show mmol/L. A reading of 8 is far more likely to be 8 mmol/L than 8 mg/dL.

If it is 8 mmol/L

= 144 mg/dL. Fasting without diabetes: Diabetes range · With diabetes before a meal: Above target

If it really is 8 mg/dL

That is 0.4 mmol/L — severely low, below the level 2 hypoglycemia threshold of 54 mg/dL (3.0 mmol/L). Most meters show "LO" below 20 mg/dL. If the person is shaky, sweaty, confused or drowsy, treat it as a severe low: 15–20 g of fast-acting carbohydrate if they can swallow safely; if not, glucagon if available, recovery position and call 911 (US) or your local emergency number.

Full explanation for 8 mg/dL →

Not urgent — but follow up

Without diabetes: this is above normal both fasting and 2 hours after eating — ask your doctor for an HbA1c or a glucose tolerance test.
With diabetes: fine after a meal, above the pre-meal target if fasting. Look at the pattern over several days and discuss it at your next review.
Note the time and whether you had eaten — the same number means different things fasting and after a meal.

If you don't have diabetes — reading 8 mmol/L (144 mg/dL)

Two hours after eating, 8 mmol/L (144 mg/dL) is in the prediabetes range (7.8–11.0 mmol/L = 140–199 mg/dL); fasting it would be in the diabetes range. Have your doctor check an HbA1c or a glucose tolerance test.

Fasting prediabetes cut-off: the ADA uses 5.6 mmol/L (100 mg/dL); the WHO uses 6.1 mmol/L (110 mg/dL). This site follows the ADA.

Fasting (8+ hours without food)

Diabetes range

2 hours after eating (or glucose tolerance test)

Prediabetes range

If you have diabetes — reading 8 mmol/L (144 mg/dL)

8 mmol/L (144 mg/dL) is above the pre-meal target (4.4–7.2 mmol/L = 80–130 mg/dL) but within the after-meal target (below 10.0 mmol/L = 180 mg/dL). As a fasting reading it suggests your overnight control could improve.

Before a meal / fasting

Above target

1–2 hours after a meal

In target

Targets for most non-pregnant adults (American Diabetes Association (ADA) Standards of Care). Your own targets may be different — for example in pregnancy, for children, older adults or people prone to lows. See pregnancy targets.

144 mg/dL as an average: HbA1c 6.6%

If 144 mg/dL were your average glucose over two to three months, it would match an HbA1c of about 6.6% (diabetes range, but within the common treatment goal of below 7%). A single reading says little about your HbA1c — it is the long-term average that counts. Learn more in how to measure blood sugar.

Make sure the number is right

Wash and dry your hands before a finger-stick: fruit juice or sugar on the skin can raise the result a lot.
Home meters may differ from a lab value by up to about 15%. At 144 mg/dL that means roughly 122–166 mg/dL.
CGM sensors measure tissue fluid and lag 5–15 minutes behind blood when glucose changes quickly — confirm lows with a finger-stick.

Check another reading

Nearby values

Sources: ADA Standards of Care · ADAG study (HbA1c and average glucose) · WHO: Definition and diagnosis of diabetes · MedlinePlus: Blood glucose test

This page explains one reading in general terms. It is not a diagnosis or a treatment instruction. Follow the plan agreed with your doctor or diabetes team.