Medical Specialty >> Endocrinology

Doctors Lounge - Endocrinology Answers

Back to Endocrinology Answers List

If you think you may have a medical emergency, call your doctor or 911 immediately. Doctors Lounge ( does not recommend or endorse any specific tests, physicians, products, procedures, opinions, or other information that may be mentioned on the Site.

DISCLAIMER: The information provided on is designed to support, not replace, the relationship that exists between a patient/site visitor and his/her physician. Please read our 'Terms and Conditions of Use' carefully before using this site.

Date of last update: 10/17/2017.

Forum Name: Diabetes

Question: Confused on Blood Glucose Results.

 ovationlady - Mon Jul 26, 2010 11:48 am

I have been checking my blood for the past 2.5 weeks. My fasting blood sugar
level is typically between 127 and 139. This is after 8-10 hours of fasting.
Is this normal? After I eat, level is up to 192 with an average of 160s. I
know it depends on what you eat, but still is this normal? I am extremely
tired all the time yet I get plenty of hours sleep at night. I am extremely
thirsty all the time. After eating a meal, 30 minutes later I am very
hungry. I use the bathroom up to 11 times each day with a couple of times
during the night. My NP say I am in the normal range, but from what I read, I am not sure. Any thoughts/comments? Thank you, Linda
 Dr.M.Aroon kamath - Wed Jul 28, 2010 2:26 am

User avatar Hi,
Your confusion is not in any way unique, as you will appreciate as we go along.

The confusion stems from three main aspects.
a) the various definitions in this context and the recommended 'normal' values/ranges,
- the techniques of blood glucose analysis(plasma glucose vs whole blood glucose vs capillary glucose), and
- difficulties in conversions between mmol/L and mg/dl.

(1 mmol/l = 18 mg/dl).

American Diabetes Association (ADA) and the World Health Organization (WHO) guidelines are generally followed.There are guidelines as well (ex; European, Australian).

At the outset, one should remember that there are different sets of diagnostic criteria for
- clinical and

- for epidemiological settings.

In epidemiological settings, for studies involving high-prevalence populations or selective screening of high-risk individuals, a single measurement - the glucose level 2 h following a glucose load (post-glucose load)- will be enough to describe presence of impaired glucose tolerance (IGT).

For epidemiological purposes the American criteria(1997) recommend the use of fasting plasma glucose concentration >= 7.0 mmol/l, in contrast with the current World Health Organisation criteria of 2 hour glucose concentration >= 11.1 mmol/l for diagnosis of diabetes.
The application of the American criteria on European populations induced changes in prevalence of diabetes ranging from a prevailing reduction of 4.0%, to an increase of 13.2%!. Thus, the changeover to fasting plasma glucose will inevitably cause an increase in the prevalence of diabetes in some European populations.

In clinical practice however, diagnostic criteria include
= two separate fasting plasma glucose (FPG) values >126 mg/dL,
- a random glucose ≥200 mg/dL,or
- two separate 2-hour oral glucose tolerance
test (OGTT) glucose values ≥200 mg/dL.

The use of hemoglobin A1c (HbA1c) for the diagnosis of DM is not recommended at this time.Furthermore, stress induced evere hyperglycaemia should not be regarded as diagnostic of diabetes.It is better to review after stabilization of the primary condition.

Two factors significantly affect glucose measurements:
- the hematocrit and
- delays after blood drawing.

The disparity between venous and whole blood levels amplifies
when the hematocrit is high(newborns,or polycythemia).
The specimen should be drawn into a fluoride tube or processed immediately to separate the serum or plasma from the cells. Delays will result in the measurable glucose being gradually lowered by continuing in vitro metabolism of the glucose at a rate of approximately 7 mg/dL/hr. This aggravates in the presence of leukocytosis.

Whole blood glucose levels (ex;by glucometers) are about 10%-15% lower than venous plasma levels.For more on this please visit the following link.

I hope this information is helpful and does not compound your pre-existing confusion! You need to consult your regular doctor who will be in a better position to correlate your clinical picture with your blood sugar values.
Best wishes!

| Check a doctor's response to similar questions

Are you a Doctor, Pharmacist, PA or a Nurse?

Join the Doctors Lounge online medical community

  • Editorial activities: Publish, peer review, edit online articles.

  • Ask a Doctor Teams: Respond to patient questions and discuss challenging presentations with other members.

Doctors Lounge Membership Application

Tools & Services: Follow DoctorsLounge on Twitter Follow us on Twitter | RSS News | Newsletter | Contact us