A study is evaluating a new screening tool for prostate cancer. A total of 500 participants are enrolled in the study. Among all participants, 180 were diagnosed with prostate cancer through biopsy, but 8 of them had received a negative screening result. Among participants without prostate cancer, 70 were falsely screened positive.
What is the positive likelihood ratio of this new screening tool?
A study is conducted to evaluate the efficacy of the faecal immunochemical test as a screening tool for bowel cancer in individuals over the age of 50. The study involves 1000 patients, and 100 of them test positive for the test. Out of these 100 patients, 60 are diagnosed with bowel cancer through colonoscopy. On the other hand, 10 patients who tested negative for the test were later found to have bowel cancer.
What is the nearest whole number likelihood ratio for a positive test result?
A doctor investigating the number of missed appointments (DNAs) for 10 patients, reveals the following data set.
Patient number vs Number of DNAs in 12 months
1 vs 0
2 vs 3
3 vs 1
4 vs 45
5 vs 2
6 vs 0
7 vs 1
8 vs 4
9 vs 4
10 vs 2
How would you best summarize the average number of missed appointments for these patients?
A new medication aimed at preventing outbreaks of shingles is being tested in clinical trials. One hundred participants are administered the new medication. Over a three-month period, 10 of the participants experience a shingles outbreak. Meanwhile, in the control group, 300 participants are given a placebo. During the same time frame, 50 individuals in the control group experience a shingles outbreak. What is the relative risk of experiencing a shingles outbreak while taking the new medication?
A quick finger-prick blood test is created to aid in the detection of deep vein thrombosis. A study involving 1,000 patients is conducted to compare the test to current standard methods:
DVT present DVT absent
New test positive 200 100
New test negative 20 680
What is the new test’s specificity?
A 32-year-old woman with a body mass index of 51 kg/m2 presents to you seeking guidance on weight management, including the use of medication. You recently reviewed a systematic review of RCTs comparing orlistat to placebo for weight management, which included an asymmetrical funnel plot. What type of bias could this indicate?
A 50-year-old patient presents you with a research paper on a new screening test for diagnosing breast cancer that is currently on trial. The test is being compared to the current gold standard screening test, mammography. The patient is interested in this test as she finds mammograms uncomfortable and wants to know how the new test compares to the standard screening.
Given the following data, what is the specificity of the new test?
Positive mammogram Negative mammogram
Test positive 32 150
Test negative 15 439
An academic researcher is investigating the efficacy of a new treatment for elderly patients with osteoporosis. Prior to commencing her own study, she intends to conduct a meta-analysis to consolidate existing findings on the subject. As part of her meta-analysis, she must evaluate whether publication bias exists in the literature.
What is the most effective method for the researcher to detect this?
A 42-year-old male presents with fever, productive cough, and difficulty breathing. During his workup, a urine pneumococcal antigen test is performed. According to a study, this test has a sensitivity of 68% and a specificity of 99%. What does the specificity value of 99% refer to?
A new rapid diagnostic test is developed to diagnose Alzheimer’s disease. The test is based on measurement of certain biomarkers in the blood that are associated with the disease. The sensitivity and specificity of the test is 80% and 85%, respectively.
What is the likelihood ratio for a negative test result?