Spirometry calibration

Question 1

What is calibration?

Answer 1

Comparing the measurements of 2 instruments (one with known magnitude and correctness which you measure the other against).

Question 2

What is verification?

Answer 2

Checking an instrument and ensuring any error is within permissible limits.

Question 3

How are spirometers verified?

Answer 3

Injecting known volume, 3 litre syringe is used.

Question 4

When is the verification acceptable?

Answer 4

If it is +/- 3% of the true volume.

Question 5

Does calibration matter?

Answer 5

Yes, could lead to misdiagnosis or make it look abnormal (should report until calibrated).

Question 6

When should calibration be verified?

Answer 6

Every morning, if room temp changes by 5 degrees. Calibration syringe should be checked yearly.

Question 7

How to verify spirometer using healthy physiological control?

Answer 7

Perform 20 consecutive spirometry tests, by same operator at similar time of day.
-Add together 10FEV1, 10RVC, 10FVC and 10 PEF and divide by 10 to get average
-work out 5% either side to represent normal variability