Introduction
The two screening tools under analysis are STI Screening and NAT Testing. Sexually transmitted diseases are one of the most dangerous as they might spread very quickly. To identify the most relevant tool for disease detection and prevention, it seems necessary to properly examine both of them.
STI Screening
STI Screening is associated with highly sensitive screening tests, in other words, they almost do not give false-negative results. The Sexually Transmitted Infection (STI) Screening system uses artificial HIV proteins that detect specific antibodies developed by the body in response to viral proteins (Zenilman & Shahmanesh, 2012). Once antibodies are trapped, they can be identified by reagents that are used together with an indicator such as an enzyme resulting in the change of color. Changes in the color are read by a machine determining the result. Speaking of the odds ratio, the STI Screening can identify HIV infection in 3-5 weeks after the contamination in most cases. The specificity of the STI Screening identifies whether the person has a disease or not. However, the identification of different diseases requires different tests. The positive predictive value (PPV) of the screening is 50 percent while the negative predictive value (NPV) is five percent.
NAT Testing
Another type of screening tool is Nucleic Acid Testing (NAT) that is also known as Nucleic Acid Amplification Testing (NAAT). It is used for the amplification of HIV RNA to facilitate the identification of the virus. Due to the extremely high sensitivity of NAT tests, a window period is short, but there are frequent false-positive results. In particular, the PPV of the tool consists of 60 percent, and the NPV is 7 percent. Therefore, positive results should be confirmed by applying a standard test for HIV as soon as possible. Given the high cost of NAT tests, they do not use regularly and are not cost-effective for testing large groups of people. As a rule, NAT tests are used for the detection of HIV in infants and blood banks. What is more, they are significant for the diagnosis of primary or recent infections. The specificity of the tool is 98 percent (Zenilman & Shahmanesh, 2012). The odds ratio is approximately 11 days (Hans & Marwaha, 2014).
Additional Means to Evaluate Screening Tools
It is also useful to apply the Open Source Epidemiological Statistics for Public Health tool while assessing the effectiveness of screening tools. After receiving the necessary information, it might be compiled and entered into so-called 2×2 contingency tables. Tables are intended to conduct further statistical processing of materials by comparing two samples. Among confounders, in other words, variables that distort results of the screening, one might note age or related diseases. A properly designed study eliminates confounders in the case if the researcher knows the object of the study and constantly expects the occurrence of errors. Nevertheless, there are such effect modifiers as age or immunization. The effect modifier alters the initial causative factor. For instance, age is an effect modifier in plenty of diseases or the immunization that modifies consequences of exposure to infectious agents.
Conclusion
In conclusion, we consider that described tools are rather significant and useful to identify and prevent the spread of sexually transmitted diseases. Besides, it seems appropriate to investigate the above topic among 20-35 age groups with different ethnicities and incomes as they are exposed to the disease more than others. We believe that the logic on the decision of screening tools is appropriate as they are relevant and successfully used in nowadays medicine. Speaking of the defined confounders and interactions, we agree with the decision because it reflects principal aspects.
References
Hans, R., & Marwaha, N. (2014). Nucleic acid testing-benefits and constraints. Asian Journal of Transfusion Science, 8(1), 2-3.
Zenilman, J. M., & Shahmanesh, M. (2012). Sexually transmitted infections: Diagnosis, management, and treatment. Sudbury, MA: Jones & Bartlett Learning.