To observe the effect of increasing sensitivity, assume a blood sugar screening level of 130 mg percent, with a sensitivity of 44.3% and a specificity of 99.0%. Set up a two by two table with the appropriate numbers in each cell. Calculate the following values when the number of persons screened is 10,000 and the prevalence of undetected diabetes is 1.5%. Round to the nearest whole number, but only after you have completed all the calculations down through and including item e). (1 pt. per box including totals)

Question

To observe the effect of increasing sensitivity, assume a blood sugar screening level of 130 mg percent, with a sensitivity of 44.3% and a specificity of 99.0%.  Set up a two by two table with the appropriate numbers in each cell.  Calculate the following values when the number of persons screened is 10,000 and the prevalence of undetected diabetes is 1.5%.  Round to the nearest whole number, but only after you have completed all the calculations down through and including item e).    (1 pt. per box including totals)
  		   ills		wells		    Total people
Pos tests			
Neg tests

Total tests

Calculate the following values:
a.	The percentage of false positives among all those without disease (the type I error rate). (2 pts.) 
b.	The percentage of false negatives among all those with disease (the type II error rate). (2 pts.) 
c.	The predictive value of a positive test. (2 pts.)  
d.	The predictive value of a negative test. (2 pts.) 
e.	Based on the calculations above, how many false positives and false negatives will occur if 100,000 people are screened? (2 pts.)
f.	Explain the clinical significance of a diagnostic test’s sensitivity and specificity. Be specific in your explanation by using a diagnostic test as an example. (6 pts.)
g.	If you were the director for the diabetes screening program would you prefer to screen at 130 mg or 180 mg percent? Explain why. (6 pts.)