The Nursing Clinic located at the Judith Fisher Centre.
Email address: LasquetiHealthCentre@gmail.com
Nurse: Dianne McClure RN/MN
Cell: 250-240-5712 | Home: 250-752-7419
Clinic phone (during clinic hours): 250-333-8891
Hours: Drop in Thursday from 11:00am – 3:00pm
If any one has a health related topic that they would like to see in the Medicine Wheel feel free to email me your suggestions at: firstname.lastname@example.org
Dr. McClure (Larry) thought he would complete his discussion on “tests”.
We learned last month how a test performs depends on the characteristics of the test as well as the prevalence or the likelihood of the disease.
How can we improve diagnostic accuracy? First we can adjust the test.
Many tests have cut off points that can be shifted to improve the sensitivity (fewer false negatives) of the test however this will often result in lowering the specificity (more false positives).
The choice on where to place cut off points depends on the relative importance of balancing not detecting people with the disease versus labeling people who actually DO NOT have the disease as being positive for the disease.
In the case of COVID testing it would appear that a decision was made to maximize the sensitivity of the test in order to detect all cases for the purposes of quarantine and contact tracing.
A second way to improve the diagnostic accuracy is to combine tests to increase the likelihood of having the disease. Again if we look at COVID testing here in BC, people were directed to a clinical questionnaire (which is a form of a test). Only those that tested positive on the questionnaire were advised to test for COVID. Use of the clinical questions (questionnaire) to decide on who should test effectively increased the likelihood of having Covid in those being sent for testing and therefore the performance of the test. Some provinces allowed people without symptoms to test but we are now all aware given the low likelihood of disease in this group the test would not perform well in these circumstances.
A brief note on rapid tests; They almost always have lower sensitivity and specificity than regular tests which makes it difficult to use a rapid test on asymptomatic (people without symptoms) with a low likelihood of disease. They produce a high number of false positives.
If you have further questions please feel free to contact Larry or myself.
I hope you are all enjoying this beautiful Spring!
Best, Larry and Dianne