MPH 504 - Epidemiology (Module 5 - CBT) Essay Example | Topics and Well Written Essays - 500 words

MPH 504 - Epidemiology (Module 5 - CBT) - Essay Example However this also eliminates high number of HIV infected individuals due to reduced sensitivity causing undesirable social and health problems (such as risk of spreading the disease and delay for the treatment). To overcome the problems of both extremes A is the most suitable OD ratio to establish the cutoff. 6. Director of Blood Bank: HIV is a deadly disease with no cure. Therefore the intention of screening the donated blood samples against HIV is to totally protect blood receivers from being infected with HIV. Therefore director of Blood Bank has to set the cut off where he can eliminate almost all the HIV infected blood samples. In other words he has to attain 100% sensitivity. Thereby he has to draw the cutoff line for OD ratio at B eliminating the risk of possible false negatives. However this decision dramatically reduces the specificity by increasing the number of false positives. This leads to rejection of higher number of healthy blood samples. Investigator: The investigator needs to select high risk HIV infected individuals to test the efficacy of his potentially toxic antiviral drug through a clinical trial. Since the antiviral drug is potentially toxic he has to select only HIV infected individuals without any false positives. Consequently he has to achieve 100% specificity eliminating all false positive. In doing so he should draw the cutoff line for OD ratio at C. However as a result of this decision he has to reject high number of HIV infected individual who tested negative due to low sensitivity resulted from the newly defined cutoff. This makes him recruit a larger sample (than expected) to get the required number of eligible