Avian influenca - Test 3

Finally you use the same ELISA test (SE = 98.0%, SP = 97.5%) to investigate clinical signs in a single animal. The flock of 10,000 chickens the animal comes from appears clinically health and your country is officially free of AI virus.

iDevice icon Complete the contingency table
Complete the contingency table by typing in the values (numbers only). Use the calculator if required.

  AI +
AI - Total
ELISA +

ELISA -

Total

 

 

 

 

 

 


Calculator:


  

iDevice icon Calculate prevalence and predictive values

Calculate the predictive values for both a positive and negative test result under the assumption that the true prevalence in the population is 0%; i.e the country is free from the disease.

Type in the values (whole numbers only):

The true prevalence is , thus there are AI+ and AI- animals.

The number of true positive is and the number of false negative is .

The number of true negative is . Thus, there are false positive animals.

The test positive predictive value is .

The test negative predictive value is .

  

iDevice icon Discussion and interpretation
How would you interpret a positive result and what would you recommend in this case (which other measures would you implement)?
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