Application of predicted spirometry values

Question 1

Name some statistics values

Answer 1

-normal distribution
-variance
-standard deviation

Question 1

How do you calculate the test result as a percentage of predicted value?

Answer 1

test result/predicted value x100

Question 2

Describe the normal range of predicted values

Answer 2

Normal range is the predicted value +/- 1.64 SD

-LLN at -1.64 SD and the ULN at +1.64SD

-includes 90% of the population so results below the normal range are in the bottom 5% of the population

Question 3

How do you calculate the upper and lower limits of normal?

Answer 3

-calculate the predicted value/derivated of reference

-now use the residual standard deviation to calculate the range

ULN- predicted value + 1.64 x RSD

(in males RSD predicted FEV1 is 0.51)

Question 4

What is the SR score?

Answer 4

-standard residual

-known as the z score​

-instead of giving the normal range, the test result can be expressed in terms of how many standard deviations it is from the predicted value​

-the number of standard deviations from the mean is called the z-score (or standard residual (SR) score) ​
-This can be calculated for each value measured​

SR score = (value – predicted)/SD​

Question 5

What is the normal range for the Z score?

Answer 5

between -1.64 (LLN) to +1.64( ULN)