Question

1. Serum cotinine is a metabolic product of nicotine, which is often used to measure the smoking status Below are data collected as part of a study in which the smoking status was ultimately determined Smokers (N 1984) DISEASE 120 150 Non-Smokers (N NO DISEASE 2500 152 Serum cotinine level (ngimi) 2814) 14-49 50-99 150 243 25 100-149 150-199 200-249 275 278 312 456 250-299 10 300+ 2. Suppose a serum cotinine level of 100+ ng/mL is proposed as a screening criterion for smoking status. Create a 2x2 table for these data 3. In the table you created above, label TP, FP, FN, and TN in the appropriate cells. 4. What is the sensitivity of the test? How do you interpret this result? Express the sensitivity as a proportion. 5. What is the specificity of the test? How do you interpret this result? 6. What is the positive predictive value for the test? How do you interpret this result if you had a patient? 7. What is the negative predictive value for the test? How do you interpret this result?

Answer 1

1. serum cotinine is a metabolic product of nicotine, which is often used to measure the smoking status. BELOW ARE DATA collected as part of a study in which the smoking status was ultimately determined.

Answer :-

Serum cotinine test is performed to detect the recent exposure of the individual to tobacco. this is becuase; tobacco contains cotinine and it can be detected in saliva, blood, and also in urine.

individual having smoking propensity will have high cotinine esteem in serum morethan 300ng/ml

non-smokers for the most part have cotinine esteem under 10ng/ml.

moderate to light smokers have 10-100mg.ml of cotinine esteem.

according to the given information, 1984 people (smokers) were screened for cotinine. every one of them have variable estimation of cotinine levels in serum. indeed, even in them, a portion of the people demonstrate ordinary cotinine esteems as of non-smokers. this shows, those people are smokers yet they haven't presented to tobacco as of late.

like savvy; even non-smokers(2814) were screened for cotinine esteem. in this larger part of the people cotinine values are typical however even in non-smokers, a few people indicate high cotinine vaue. this shows, these people are non-smokers yet presented to tobacco as of late at high rates. in this way, they are put under non-malady people.

from this, it is clear that, one side, all the smokers are positive for the test and called as truth positive. in contrast, all the non-smokers are negative for the test, called as truth negative.

apart from these two cases, they are false positive and false negative.

the people who are smokers, sick having low cotinine esteem demonstrate false adverse test.

the people who are non-smokers, non-sick yet at the same time having high cotinine esteem are false constructive indiviudals.

2.

As per the data, 100 ng/ml value is taken as criteria for screening.

so, the individuals above 100 ng/ ml are said to be negative and below 100ng/ml are said to be postive.

3. in the above made table, false positive and false negative are composed beneath the quantity of people.

4. sensititvity is the measure fo any test, which demonstrates the capacity of the test to recognize the right positive example among every one of the people. according to the consequences of the given information, the test can't distinguish the right positive example. this can be advocated in light of the fact that; the test have approach proprtions of false positve and false negative people. as far as proprtion, the test ought to have the capacity to keep all the positive people on one side and antagonistic people on the other.

6. The interpretation of results says that, the positive predictive value is highest value of cotinine, 300+ ng/ml.

7. the negative predictive value is below 10mg/ml.

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