Published online by Cambridge University Press: 02 May 2020
Up to this point, we have discussed the accuracy of dichotomous tests – those that are either positive or negative for the disease in question. Now, we want to consider the accuracy of multilevel tests – those with more than two possible results. As discussed in Chapter 2, the results of such tests can be ordinal if they have an intrinsic ordering, like a urine dipstick test for white blood cells, which can be negative, trace positive, or positive. Test results also can be discrete (having a limited number of possible results, like the dipstick test) or continuous, with an essentially infinite range of possibilities (like a serum cholesterol level or white blood cell count).