| relative incompetence | Imperfect closure of a cardiac valve, in consequence of excessive dilation of the corresponding cavity of the heart. (05 Mar 2000) |
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| relative leukocytosis | An increased proportion of one or more types of leukocytes in the circulating blood, without an actual increase in the total number of white blood cells. (05 Mar 2000) |
| relative molecular mass | The sum of the atomic weight's of all the atoms constituting a molecule; the mass of a molecule relative to the mass of a standard atom, now 12C (taken as 12.000). Relative molecular mass (Mr) is the mass relative to the dalton and has no units. See: atomic weight. Synonym: molecular mass, molecular weight ratio, relative molecular mass. (05 Mar 2000) |
| relative polycythemia | A relative increase in the number of red blood cells as a result of loss of the fluid portion of the blood. (05 Mar 2000) |
| relative refractory period | The period between the effective refractory period and the end of the refractory period; fibres then respond only to high intensity stimuli and the impulses conduct more slowly than normally. (05 Mar 2000) |
| relative risk | <epidemiology> The proportion of diseased people amongst those exposed to the relevant risk factor divided by the proportion of diseased people amongst those not exposed to the risk factor. This should be used in those cohort studies where those with and without disease are followed to observe which individuals become diseased. (05 Dec 1998) |
| relative scotoma | A scotoma in which there is visual depression but not complete loss of light perception. (05 Mar 2000) |
| relative sensitivity | The sensitivity of a medical screening test as determined by comparison with the same type of test; e.g., sensitivity of a new serological test relative to sensitivity of an established serological test. (05 Mar 2000) |
| relative specificity | The specificity of a medical screening test as determined by comparison with the same type of test (e.g., specificity of a new serological test relative to specificity of an established serological test). (05 Mar 2000) |
| relative value scales | Coded listings of physician or other professional services using units that indicate the relative value of the various services they perform. They take into account time, skill, and overhead cost required for each service, but generally do not consider the relative cost-effectiveness. Appropriate conversion factors can be used to translate the abstract units of the relative value scales into dollar fees for each service based on work expended, practice costs, and training costs. (12 Dec 1998) |
| relative viscosity | The ratio of the viscosity of a solution or dispersion to the viscosity of the solvent or continuous phase. (05 Mar 2000) |
| 5-year relative survival rate | <statistics> The likelihood that a patient will not die from causes associated with his or her cancer for at least 5 years after diagnosis. This is the standard many professionals use when determining someone a survivor of cancer. (16 Dec 1997) |