Please answer if you know it and can answer it fully. I have posted it before an
ID: 197994 • Letter: P
Question
Please answer if you know it and can answer it fully. I have posted it before and got incorrect answers. (Yes, this is a sequence)
11. Upon returning from a 4-month study abroad experience in the Philippines, you begin to experience frequent pain and discomfort in your stomach and lower esophagus. Your doctor suggests this could be due to simple readjustment to western-style food, or could be due to an infectious agent - it turns out that roughly 19% of travelers who visit Southeast Asia for periods of 3 months or longer are exposed to and infected with Helicobacter pylori, a bacterium that is associated with peptic ulcer disease. Your doctor tests for this bacterium using a diagnostic that has 86% specificity and 94% sensitivity. Given this information, explain your reaction to the following two outcomes (use numbers to back up your statements and be sure to show your work to ensure partial credit): Scenario 1: the test results are positive how concerned are you that you are actually infected with this bacterium? (4 points) Scenario 2: the test results are negative are you confident that you are really uninfected? (4 points)Explanation / Answer
Scenario 1:
1) Stool antigen testing is the most recently specified testing for the infection of Helicobacter pylori, it is performed four weeks after treatment.
2) There are two types EIA based and other based on immunochromatography, but EIA based is the most accurate done using mixture of peroxidase conjugated G.Pylori antibodies and peroxidase conjugated monoclonal anti H Pylori.
3) Performance characteristics is reduced for water diarrheal stools or for asymptomatic individuals or even few drugs like antimicrobials, proton pump inhibitor and bismuth preparations which may give false negative results, in such cases test has to be repeated.
4) Positive results (antigen detected) is the indicative of H Pylori Disease. postitive result after 7 days after therapy is indicative of ineffective treatment or recurrence, but this has to be repeated after 4 weeks post treatment, negative this time indicates eradication of the infection, but intermediate results require testing on new specimens,
Scenario 2:
Negative Result (antigen not detected) indicates the absence of H.Pylori infection or antigen level below the assay limit of detection
1) Negative after 7 days confirms eradiction of the infection
2) Negative after 4 weeks post treatment also indicates the eradication of infection
3) False negative results can be obtained when patient is given drugs metioned above like antimicrobials, proton pump inhibitor and bismuth preparations two weeks prior to sample collections.