Red cross Health Dictionary

A study that measures the prevalence of health outcomes or determinants of health, or both and other variables of interest in a population at a point in time or over a short period.... cross-sectional study

A type of malocclusion in which some or all of the lower front teeth overlap the upper front teeth.... crossbite

A form of cost-effectiveness analysis of alternative interventions in which costs are measured in monetary units and outcomes are measured in terms of their utility, usually to the individual, e.g. using QALYs.... cross-utility analysis

Occurs when some participants who are assigned to the treatment group in a clinical study do not receive the intervention or receive another intervention, or when some participants in the control group receive the intervention (e.g. outside the trial). If these crossover participants are analysed with their original groups, this type of bias can “dilute” (diminish) the observed treatment effect.... crossover bias

A trial in which each of the groups involved will receive each of the treatments, but in a randomized order: that is, they will start in one arm of the trial, but will deliberately ‘cross over’ to the other arm(s) in turn.... crossover trial

A type of strabismus (squint) in which one or both eyes turns inwards relative to the other.... cross-eye

A procedure to determine compatibility between the blood of a person requiring a blood transfusion and that of a donor.

Red blood cells from one person are combined with serum from the other.

Clumping of red blood cells indicates the presence of antibodies, showing the blood is not compatible.... cross-matching

n. see transvestism.... cross-dressing

(in genetics) the exchange of sections of chromatids that occurs between pairs of homologous chromosomes, which results in the recombination of genetic material. It occurs during *meiosis at a *chiasma.... crossing over

see intervention study.... cross-over trial

any technique that produces an image in the form of a section through the body with the structures cut across. The main techniques are *ultrasonography, *computerized tomography, *magnetic resonance imaging, and some *nuclear medicine techniques (see positron emission tomography; SPECT scanning). If a series of thin-section images is stacked they can be ‘cut’ through to show other planes or allow reconstruction of three-dimensional images.... cross-sectional imaging