BloodGlucoseValueUnderstand every reading

Blood Glucose 19 tested - mmol/L or mg/dL?

LOmg/dL1.1 mmol/L

You chose mg/dL: 19 mg/dL (1.1 mmol/L) is a severe low — act now (see the box below). On meters outside the US a reading of 19 usually means 19 mmol/L; that reading is explained in the second card.

19 mg/dL, as you entered it

That is 1.1 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.

If you meant 19 mmol/L

= 342 mg/dL. Fasting without diabetes: Diabetes range · With diabetes before a meal: Very high

Full explanation for 342 mg/dL →

Treat a low now

  • Take 15–20 g of fast-acting carbohydrate: 4 glucose tablets, ½ cup (4 oz) of juice or regular soda, or 1 tablespoon of sugar or honey.
  • Re-check after 15 minutes. Still below 70 mg/dL = 3.9 mmol/L? Repeat. Once above 70, eat a snack or meal.
  • If the person cannot swallow safely, is confused or unconscious: give glucagon if available, put them in the recovery position and call 911 (US) or your local emergency number. Never put food in the mouth of someone who is unconscious.
  • Without diabetes: a confirmed reading this low needs a doctor to find the cause.

If you don't have diabetes — reading 19 mg/dL (1.1 mmol/L)

19 mg/dL (1.1 mmol/L) is well below normal. In people without diabetes, blood sugar rarely falls this low. If the reading is real and you have symptoms (shakiness, sweating, confusion), treat it now with 15–20 g of fast-acting carbohydrate (see the box above) and see a doctor to find the cause. Most meters show "LO" at this level.

Fasting (8+ hours without food)

Very lowScale with 19 mg/dL marked557010012619 mg/dL (off scale)

2 hours after eating (or glucose tolerance test)

Very lowScale with 19 mg/dL marked557014020019 mg/dL (off scale)

If you have diabetes — reading 19 mg/dL (1.1 mmol/L)

19 mg/dL (1.1 mmol/L) is level 2 hypoglycemia — clinically significant low blood sugar. Treat it immediately (see the box above). If it happens repeatedly, your treatment plan needs to change.

Before a meal / fasting

Level 2 hypoglycemiaScale with 19 mg/dL marked547080>130>180>24030019 mg/dL (off scale)

1–2 hours after a meal

Level 2 hypoglycemiaScale with 19 mg/dL marked5470180>24030019 mg/dL (off scale)

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.

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 19 mg/dL that means roughly 16–22 mg/dL.
  • CGM sensors measure tissue fluid and lag 5–15 minutes behind blood when glucose changes quickly — confirm lows with a finger-stick.

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Nearby values

Sources: ADA Standards of Care · ADA: Hypoglycemia · 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.