Question

Beside using standard deviation, briefly describe another method for determining assay sensitivity and specificity. What are the advantages and disadvantages of these methods?

Answer 1

The matrices method can be used for the determination of the specificity and sensitivity of an assay. If we consider the positive and the negative test there are four possibilities that the true positive, try negative, false positive,, and false negative. Thus whenever the diseased patient having "a" positive test and "c" negative test has been seen then for the determination of the sensitivity of an assay the mathematical representation will be

Sensitivity = a/(a+c)

For the determination of the specificity the negative cases of the disease condition that means the healthy individual has to be check as control which will determine whether the assay is non-specific or the specific to the given gene or protein. If "b" is variable for the positive cases in the healthy sample and "d" is the variable for the negative tests then the specificity for the same in the mathematical form will be represented as

Specificity= b/(b+d)

Advantages: This is the direct method for the determination of the sensitivity and the specificity of an assay. Thus, this can be a merit for this method

Disadvantage: This method need to have the threshold value for the determination of the negative and the positive cases of the individual in the diseased condition.