Infectious Disease Screening: Suitability for Mass Screening, Considerations Regarding Test Validity (Essay Sample)

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Infectious disease screening
Infectious disease screening
Suitability for Mass Screening
The World Health Organization (WHO) has recommendations to help in choosing an infection or a disease for mass screening. The guidelines given are the Wilson’s criteria, which give a set of ten rules that determine the suitability of a disease for mass screening. From the information given, this infection is a significant health problem and it has got a treatment. Facilities for diagnosis and treatment are also available and there is a test for the condition. The proposed policy is that every person found to be positive should be treated. From the foregoing, the disease is suitable for screening because it satisfies at least six of Wilson’s ten criteria for mass screening. However, before the program is started, it is important to establish whether the cost of screening is feasible and whether the target population finds the screening procedure acceptable. It is also important to establish whether the disease has a latency period and that its natural history is sufficiently understood.
Considerations Regarding Test Validity
In order to find out whether the test is a suitable method for screening, it is imperative to put four special measures into consideration.. The sensitivity is the proportion of diseased individuals who actually test positive, while the specificity is the proportion of disease-free individuals who test negative. The positive predictive value of the test is the fraction of people who test positive that actually have the disease while the negative predictive value gives the fraction of people who test negative that are actually disease free. A test to be considered for mass screening should have both a high specificity and high positive predictive value. This is because in mass screening the interest is finding out those who have disease and a high specificity means that anybody who tests positive is very likely to have the disease. Likewise, the positive predictive value indicates the strength of the test to establish diseased individuals.
Ethical and Economic Concerns about a Test with a Positive Predictive Value of Less Than 50% for an STD Infection
A positive predictive value of 50% means that only 50% of the people who emerge positive actually have the disease. The other half may test positive but are in reality disease-free. Considering that the test is for a sexually transmitted infection, the test may cause unnecessary anxiety among the 50% of people that test positive but do not have the disease. This is ethically unacceptable especially for an STI. Being that the test is targeted at everyone above the age of 18, the number of false positives would be enormous. This would result in enormous superfluous costs of treatment on people who do not have the disease in the first place. This is economically objectionable.
Why Clinicians May Be Overly Influenced By Negative Tests with Poor Sensitivity
Sensitivity gives a measure of how reliable a negative result is. A negative result in a test with high sensitivity is very likely correct. When the sensitivity is lower, a negative result is increasingly likely to be a false negative. In other words, a test with a low sensitivity cannot effectively rule out disease. That is why clinicians are influenced by negative tests with poor sensitivity and might want to perform a further test to ascertain that the patient is actually disease-free.
Reasons to Favor Such a Policy
Such a policy may prove useful in curbing the spread of the STI. Considering that STIs are more prevalent among people above 18 years (since more people above 18 are sexually a...