A female asked:
Disclaimer

i had a cmp done at doctors . everything was normal except anion gap at 3. my blood urea nitrogen at 21 . ( doc said cuz i fasted).. why is this low?

1 doctor answer
Dr. Douglas Arenberg
30 years experience Pulmonary Critical Care
First things 1st.: Why did you have the test? No test should be interpreted in a vacuum. Most of the time the abnormality described is pretty meaningless. But attempting to answer your question requires we know about your medical history.
Answered on Feb 11, 2016

90,000 U.S. doctors in 147 specialties are here to answer your questions or offer you advice, prescriptions, and more. Get help now:

Ask doctors free
Personalized answers
Free
Talk to a doctor
Unlimited visits
$10/month

Related questions:

A 55-year-old male asked:
Dr. Vicken Poochikian
41 years experience Internal Medicine
Don't worry.: If you feel good i i agree with your doctor not to worry now. Assuming all your electrolytes are normal .Have it checked again in few weeks. Let your ... Read More
1
1 thank
A 40-year-old female asked:
Dr. Ed Friedlander
43 years experience Pathology
It's there: It's calculated from the sodium, potassium, bicarb and chloride. In this case, the lab did it to be helpful to the physician.
1
1 thank
A female asked:
Dr. Gurmukh Singh
48 years experience Pathology
Why tested?: All laboratory results need to be interpreted in the clinical context and the doctor who ordered the tests is usually in the best position to do that. ... Read More
1
1 thank

90,000 U.S. doctors in 147 specialties are here to answer your questions or offer you advice, prescriptions, and more. Get help now:

Ask doctors free
Personalized answers
Free
Talk to a doctor
Unlimited visits
$10/month