High glucose readings 27.3 up to 33.6 mmol/L for the last week!




Question:


My readings have been very high for the last week. I am getting readings of 27.3 up to 33.6 mmol/L. What is the end result of these readings?




Emergency Quick Answer


Blood sugar readings of 27.3 to 33.6 mmol/L are extremely high. In mg/dL, this is about 492 to 605 mg/dL.


If these readings have continued for a week, you need urgent medical care now. Do not wait for an online answer or try to manage this only with water, diet, exercise, or home remedies.


The possible end result of untreated severe hyperglycemia can be dehydration, ketones, diabetic ketoacidosis, hyperosmolar hyperglycemic state, confusion, coma, or death.



Answer by Dr. Albana Greca, MD, MMedSc


Hello,


Readings between 27.3 and 33.6 mmol/L are not mildly high. They are dangerously high, especially if they have been present for several days.


What Do These Numbers Mean?


To convert mmol/L to mg/dL, multiply by 18.



  • 27.3 mmol/L is about 492 mg/dL.

  • 33.6 mmol/L is about 605 mg/dL.


These levels can cause severe fluid loss through urination, electrolyte imbalance, kidney stress, and dangerous diabetic emergencies.


Helpful page: dangerous blood sugar levels.


What Is the Possible End Result?


If very high blood sugar is not treated, it can lead to:



  • Severe dehydration

  • Diabetic ketoacidosis, especially in type 1 diabetes or insulin deficiency

  • Hyperosmolar hyperglycemic state, more common in type 2 diabetes

  • Confusion, severe weakness, or drowsiness

  • Kidney injury

  • Coma

  • Death if treatment is delayed


Should You Go to the Hospital?


Yes. With readings this high for a week, you should contact emergency medical services or go to the emergency department now, especially if you have thirst, frequent urination, vomiting, abdominal pain, weakness, confusion, rapid breathing, fruity-smelling breath, fever, infection, chest pain, or shortness of breath.


Do not drive yourself if you feel weak, dizzy, sleepy, confused, or unwell.


Helpful page: blood sugar level over 400 mg/dL.


Repeat the Test, But Do Not Delay Care


If you are able, wash and dry your hands, use a new strip, and repeat the test. Also check ketones if you have ketone strips or a blood ketone meter.


However, do not delay emergency care while repeating tests. A week of readings in this range is unsafe.


Do Not Exercise With These Readings


Exercise is not safe when blood sugar is extremely high, especially if ketones or dehydration are present. It may make the emergency worse.


Water alone is not enough treatment. Doctors may need to give IV fluids, insulin, potassium and electrolyte correction, and treatment for the cause, such as infection or missed insulin.


What Doctors May Check


In emergency care, the medical team may check:



  • Blood glucose and ketones

  • Blood acid level or bicarbonate

  • Sodium, potassium, and other electrolytes

  • Kidney function

  • Urine test

  • Signs of infection

  • Possible missed insulin, steroid use, heart problem, or another trigger


Helpful resource: is my blood sugar too high or too low?



Important Safety Note


Blood sugar of 27.3–33.6 mmol/L is an emergency-level reading. Seek urgent medical care now, especially if readings have lasted for a week or you have vomiting, dehydration, ketones, confusion, severe weakness, abdominal pain, deep breathing, fruity breath, fever, chest pain, or trouble breathing.




Doctor’s Note


The safest goal is not to drop the glucose quickly at home. The goal is to lower it safely while correcting dehydration, ketones, electrolytes, and the cause. At these levels, medical supervision is needed.




Educational safety note: This answer is for general diabetes education only and does not replace emergency medical care. Do not delay urgent treatment for blood sugar readings of 27.3–33.6 mmol/L.



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Last reviewed: July 2026.


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