Fasting for Laboratory Tests
an important role in ensuring the accuracy of their blood
tests. In order to ensure useful and precise results, it is
vital for patients to correctly prepare for the specific
blood test they are having. Although some blood tests
require no special preparation, the majority of tests
Fasting is a
common type of preparation required for certain laboratory
tests. It requires a patient to go without all or certain
foods for eight to 12 hours. Patients may also be advised
to avoid certain drinks or medications. Certain behaviors,
such as smoking, excessive exercise and dehydration may also
alter some test results. Your Healthcare Provider may ask
you to avoid these activities before testing.
How Long Should
may recommend a certain time period for fasting; if he does
not the standard amount of time is eight to 12 hours of no
food before having blood drawn. Plan to come to the
laboratory and have your blood collected early in the
morning so you'll only need to fast overnight to meet
Fasting Dos and
Do stay hydrated
by drinking plenty of water.
prescribed medications unless specifically told by your
doctor not to.
drink any other liquid than water or exercise during your
fast. Even chewing gum is off-limits.
Any of these
elements will adversely affect your test results.
Because some tests have very specific requirements,
follow your doctor's orders regarding fasting and "npo"
status (nothing by mouth--including water) before having