QuestionSBA
QuestionChoice
This is not correct. For the specificity to be 50% the test only manages to identify half of the people who do not have the condition.
10026673
d
50%
QuestionChoice
This is the sensitivity of the test. The sensitivity of a diagnostic test is a measure of how well the test correctly identifies individuals who have a particular condition or disease (true positives). Sensitivity = (True Positives) / (True Positives + False Negatives).Sensitivity = (40)/(40+20)= 0.67X100=67%
10026671
b
67%
QuestionChoice
The specificity of a diagnostic test is a measure of how well the test correctly identifies individuals without a particular condition or disease (true negatives). It can be calculated by this formula: Specificity = (True Negatives) / (True Negatives + False Positives). Specificity = (80)/(80+10)=0.89 you then multiply by a 100 to give you a percentage.
10026670
a
89%
QuestionChoice
This is not correct. For the specificity to be 100% the test correctly manages to identify all individuals without the condition i.e., no false positives.
10026674
e
100%
QuestionChoice
This is the positive predictive value (PPV). The Positive Predictive Value (PPV) is a statistical measure used to assess the proportion of individuals who test positive for a condition or disease and truly have the condition.The formula to calculate the Positive Predictive Value is as follows: PPV = (True Positives) / (True Positives + False Positives). PPV= (40)/(40+10)=0.8x100=80%
10026672
c
80%
Concept
Chapter
2693
4325
Evaluation of a diagnostic test
Topic
178
Medical Statistics
17732
A new urine dipstick is being trialled in diagnosing urinary tract infections in a group of 150 patients. The dipstick has diagnosed 50 patients with urinary tract infections. Ten of these patients did not have infections. The other 100 patients screened negative for infection. However, 20 patients did have infection on alternate testing.

What is the specificity of the new urine dipstick?
a