Skip to Main Content

We have a new app!

Take the Access library with you wherever you go—easy access to books, videos, images, podcasts, personalized features, and more.

Download the Access App here: iOS and Android. Learn more here!


(oipt′owt′) [L. optare, to wish for] To choose not to participate in a program or not to receive information about a particular product or service. In health care, to decline to participate in a recommended program, e.g., in health screening, vaccination, or research.


One-port umbilical surgery.


oral poliovirus vaccine.


operating room.


(ō′ră) [L. ora, mouths] Plural of 1os.


(ō′rad″) [oro- + -ad] Toward the mouth or oral region.


(ōr′ăl) [L. oralis] 1. Pert. to the mouth. 2. In legal usage, pert. to spoken words, not written. In law, an oral agreement or contract is a spoken agreement or contract; there is nothing written down. SEE: verbal. orally (ōr′ă-lē), adv.

oral allergy syndrome

A form of contact dermatitis of the lips, tongue, or other tissues of the mouth, usually triggered by exposure to fresh fruits or vegetables. SYN: pollen-food allergy syndrome.

oral contraceptive

SEE: contraceptive.


(ō-rā′lē) The point on the hard palate where lines drawn tangent to the lingual margins of the alveoli of the medial incisor teeth intersect the midsagittal plane.

oral fat load test

ABBR: OFLT. Measurement of serum triglyceride levels (and other circulating fat molecules) after consumption of a specified amount of liquid fat or cream, e.g., 50 g.

oral glucose tolerance test

ABBR: OGTT. A screening test for diabetes mellitus (DM), in which plasma glucose levels are measured after the patient consumes an oral glucose load. In screening patients for type 2 DM, measuring fasting plasma glucose levels or checking a hemoglobin A1c level is generally preferable to an OGTT because the former tests are simpler, cheaper, and better tolerated by patients. An OGTT reveals type 2 DM when plasma glucose levels exceed 200 mg/dL 2 hr after drinking a 75-g glucose load. Plasma glucose levels between 140 mg/dL and 199 mg/dL suggest impaired glucose tolerance.

 GESTATIONAL DIABETES MELLITUS: In pregnancy, a modified OGTT is used to screen women with risk factors for gestational diabetes (GDM), including obesity, family history of type 2 DM, age greater than 25 years, and a history of unexplained stillbirths. At 24 to 28 weeks’ gestation, a 50-g glucose load is given; 1-hr plasma glucose levels greater than 140 mg/dL constitute a positive screening result. Any patient having a positive test result should then undergo a 2-hr, 100-g OGTT to determine whether GDM is present. ...

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.