Blood test

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Low blood sugar/glucose level

Blood test
Low blood sugar/glucose level
Last update: 02/04/2020

What is low sugar/glucose level in the blood called?

  • Hypoglycemia

What is the normal level of blood sugar/glucose?

If you need to know which are the sugar/glucose reference ranges or you require more information about the role of sugar/glucose in the blood, you can visit normal sugar/glucose level in the blood

What does low blood sugar/glucose level mean?

Hypoglycemia (low blood sugar/glucose level) usually means that the pancreas produces too much insulin.

Blood sugar values are usually given in mg/dl but sometimes you can see those values in mmol/l following the International System of Units (SI). In case your values are in mmol/l you can convert them using this tool:

  • Mild hypoglycemia (55 - 70 mg/dl in adults):

    Mild hypoglycemia is not usually a cause for concern but you and your doctor need to be aware and careful if there are other symptoms associated.

    It often happens when you are suffering from diabetes and you are taking too much insulin.

  • Moderate hypoglycemia (40 - 55 mg/dl in adults):

    Moderate hypoglycemia usually causes hunger, headache, sweating and weakness.

    If you are not taking anti-diabetic drugs, it is recommended to visit your doctor. He should advise you what to do.

  • Marked hypoglycemia (30 - 40 mg/dl in adults):

    You may be hungry, sweaty and confused with blurred vision and uncoordinated movements. You can also suffer from tachycardia.

    Moderate to severe traumatic brain injury can appear with prolonged low glucose levels.

    Low glucose level due to an underlying disease is very common. For example, as a result of a small tumor in the pancreas called insulinoma. Therefore, you must look for medical assistance.

  • Severe hypoglycemia (< 30 mg/dl in adults):

    Severe hypoglycemia can be subsequent to or a consequence of another disease. Therefore, it is important to study your circumstances and any other information relevant for the diagnosis.

    With such a low value, you can have seizures, convulsions or a loss of consciousness (coma). You need to look for urgent medical attention because you are probably unable to eat or drink.

Which factors can reduce your blood sugar/glucose level?

To suffer a concreted health situation or to be taking some drugs can reduce your blood sugar/glucose level:

  • Alcohol
  • Malnutrition
  • Drugs
    • Beta blockers
      • Propranolol
    • Insulins
    • Sulfonylureas
      • Tolbutamide

Which diseases can reduce your blood sugar/glucose level?

The following diseases can explain a blood sugar/glucose level lower than normal:

What can I do to increase the blood sugar/glucose level?

If your blood sugar/glucose level is slightly low (55 - 70 mg/dl in adults) you can add sugary food to your diet (fruit juice, sweets, grapes, raisins, pineapple, etc.)

If your sugar blood is extremely low (< 50 mg/dl in adults) you should be advised to take Glucagon to regulate the rate of glucose production and counterbalance the action of insulin.

Where can I find more information about the blood sugar/glucose level?

You can visit our pages about:

Which values are considered a low sugar/glucose level in the blood?

The following values are considered to be below the normal range:

IMPORTANT: These levels are expressed in mg/dl. They are an example of a healthy man of about 45 years of age with no known disease and not taking any medication. The ranges can be different depending on the laboratory or on your personal circumstances.

Blood Sugar
Mild hypoglycemia
69 mg/dl68 mg/dl67 mg/dl66 mg/dl65 mg/dl64 mg/dl63 mg/dl62 mg/dl
61 mg/dl60 mg/dl59 mg/dl58 mg/dl57 mg/dl56 mg/dl55 mg/dl 
Moderate hypoglycemia
54 mg/dl53 mg/dl52 mg/dl51 mg/dl50 mg/dl49 mg/dl48 mg/dl47 mg/dl
46 mg/dl45 mg/dl44 mg/dl43 mg/dl42 mg/dl41 mg/dl40 mg/dl 
Marked hypoglycemia
39 mg/dl38 mg/dl37 mg/dl36 mg/dl35 mg/dl34 mg/dl33 mg/dl32 mg/dl
31 mg/dl30 mg/dl      
Severe hypoglycemia
29 mg/dl28 mg/dl27 mg/dl26 mg/dl25 mg/dl24 mg/dl23 mg/dl22 mg/dl
21 mg/dl20 mg/dl19 mg/dl18 mg/dl17 mg/dl16 mg/dl15 mg/dl14 mg/dl
13 mg/dl12 mg/dl11 mg/dl10 mg/dl9 mg/dl8 mg/dl7 mg/dl6 mg/dl
5 mg/dl4 mg/dl3 mg/dl2 mg/dl1 mg/dl0 mg/dl  
Medically reviewed by Javier Muga Bustamante Ph.D. on 02/04/2020


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