Top answers from doctors based on your search:
Disclaimer

can I have black coffee before a fasting blood test

A 38-year-old member asked:
Dr. Terri Washington
15 years experience Endocrinology
Yes: Could depending on the test, if is blood sugar or chol then coffee could make an impact.

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
A 69-year-old female asked:
Dr. Scott Diede
A Verified Doctor answered
A US doctor answered Learn more
Unlikely...: The opposite correlation is actually more likely. Intaking caffeine can actually lower your potassium level because of the diuretic effect of caffeine ... Read More
1
1 thank
Dr. Orrin Ailloni-Charas
28 years experience Anesthesiology
No. : Have the test repeated. Blood cells can break down and release potassium. If the specimen was drawn in a way that traumatized the red blood cells, or ... Read More
1
1 thank
A 65-year-old female asked:
Dr. Robert Killian
27 years experience General Practice
Fasting for Labs: Yes. There are no sugar or fat calories in black coffee.
3
3 thanks
A 21-year-old male asked:
Dr. Gurmukh Singh
48 years experience Pathology
Better to avoid it: It is better to not eat or drink any thing more than 8 hours, except taking water. For good health - Have a diet rich in fresh vegetables, fruits, who ... Read More
1
1 thank
A 35-year-old male asked:
Dr. Jeff McFadden
23 years experience Family Medicine
Don't think so: Caffeine should not affect these results. Besides these are not acute phase reactant tests and take longer to change.
1
1 thank
A 70-year-old female asked:
Dr. Milton Mintz
A Verified Doctor answered
A US doctor answered Learn more
Yes: One cup won't change your results.
1
1 thank
A 18-year-old female asked:
Dr. Gurmukh Singh
48 years experience Pathology
Depends: Blood glucose is best monitored in fasting condition. You should have fasted at least 8 hours not taken anything other than water. This result is not ... Read More
1
1 thank
A 46-year-old member asked:
Dr. Gurmukh Singh
48 years experience Pathology
You may: If thyroid blood test is the only test you are having, coffee is not likely to materially affect the results. Generally it is better to be fasting for ... Read More
A 35-year-old member asked:
Dr. Anne Larson
33 years experience Hepatology
No: In fact, coffee has been shown to lower ast and alt.
A 29-year-old female asked:
Dr. Gurmukh Singh
48 years experience Pathology
No and No: Coffee does not give you cancer and you do not need a blood test. Incidentally there is no good blood test for cancer.

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