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base excess

The difference between the normal and the actual buffer base concentration in a blood sample when titrated by strong acid at pH = 7.40 and PCO2 = 40 mm Hg. The base excess is usually determined indirectly using measured values for pH and PCO2 and then calculated using known relationships.

b. e. of blood The substance concentration of base in whole blood determined at a pH of 7.40 and PCO2 of 40 mm Hg. This measurement helps one assess the relative contribution of respiratory versus metabolic components in acid-base imbalances in the blood.

b. e. of extracellular fluid ABBR: BE (ecf). The substance concentration of base in extracellular fluid determined at a pH of 7.40 and PCO2 of 40 mm Hg. Because this quantity cannot be determined directly, a model of extracellular fluid is used as a basis. The model consists of one volume of blood plus two volumes of plasma. As with the base excess of blood, this quantity helps one assess the respiratory versus metabolic components in acid-base balance. In contrast to the base excess of blood, the base excess of extracellular fluid is said to be more representative of the acid-base status of the accessible fluid compartment and thus more appropriate for deciding on and evaluating therapy.


(bās′līn″) A known or initial measurement used as a starting point against which future measurements can be contrasted (such as temperature or blood pressure). SEE: base line.


(bās′plāt″) In dentistry, a temporary, preformed shape made of wax, metal, or acrylic resin that represents the base of a denture. It is used to assess the relations of maxillary-mandibular teeth or to place artificial teeth in a denture preparation.

base-rate neglect

A contributor to diagnostic error in which a clinician fails to consider the prevalence of a disease in a population before making a diagnosis.


1. In chemistry, possessing the properties of a base. 2. Fundamental.


(băs″ĭd-ē-ŏb′ŏ-lŭs) [NL] A genus of filamentous fungi (of the class Zygomycetes) found in soil, decaying vegetation, and the spore of amphibians, bats, and reptiles. It can cause cutaneous, subcutaneous, gastrointestinal, and blood vessel infections in humans. Human infections are reported mostly from Africa, South America, and tropical Asia.


(bă-sid″ē-ō-mī-sēt′ēz″) In one system of taxonomy, a class of the true fungi that contains mushrooms, bracket fungi, the plant parasites rusts and smuts, and the human parasite Cryptococcus. This class is equivalent to the phylum Basidiomycotina in another system of taxonomy. Mushroom toxins may be lethal to humans if ingested, and spores of these fungi may cause allergic asthma. SEE: Basidiomycotina...

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