Extras for test 1 (intro stuff) Flashcards
What is the type of laboratory used by the campus clinic?
Commercial laboratory like quest diagnostics.
Name 5 indications for ordering laboratory tests?
- Confirmation of a clinical impression or establishment of a diagnosis. 2. Rule out a diagnosis. 3. Monitor therapy. 4. Establish a prognosis. 5. Screen for health; preventative medicine.
What is wellness screening?
Testing asymptomatic individuals who are basically healthy.
What type of diseases should be screened for with a wellness screening test?
prevalent, can be detected before clinical findings develop, are treatable, have harmful consequences if left untreated.
What is acuracy and what is percision?
Acuracy- Correctness. How close a test result comes to the true biologic value. Percision- reproducability, how consistant a test result is via multiple testing of the same specimen.
What is sensitivity and specificity?
Sensitivity- True-positive, A highly sensitive test will rule negatives out. Specificity- True-negative, A highly specific test will rule positives in.
In order to detected a disease a tests needs maximum what?
Sensitivity.
If a test has a very high sensitivity what will specificity be like and what will this mean?
specificity will probably be low, and this results in healthy people being labeled as sick.
A good screening test will have high what?
High sensitivity so it will catch almost all true-positives, but it will include people who are not sick.
What type of test will have a high specificity?
A confirmatory.
What type of test is used when there is high clinical evidence of a disease?
A highly specific.
What are reference ranges?
Patients test results are reported along with a numerical range of test values that are found in healthy individuals.
How are reference ranges RR established?
Testing on a large number of healthy individuals, then perform a statistical analysis and the results ideally represent a gaussian distribution.
Where will the healthy numbers come from in a RR?
plus or minus 2 standard deviations and this will include 95% of the healthy people so 5% of healthy people will be outliers.
RR are of most value when?
When there are age, gender, and population specific.
What are the test result values given as?
In USA- conventional units. Everywhere besides the USA- SI units or International units which are purely metric.
What are the host factors that add variablity to test results?
age, gender, race.
What is a coefficient of variation (CV)?
a statistical evaluation to determine if the variation of test results from multiple analyses of the same sample is acceptable. The lower the CV the better.
What will make a CV high?
Analytic variation due to methodology. So manual methods can have a CV of 10-15% and automated CV are a few %.
Give some examples of improper patient instructions that can be sources of error in laboratory testings?
Poor patient compliance with fasting vs. non-fasting. Collection of specimen. Exercising prior to test.
What is a profile or panel testing?
Collection of different tests related to a particular organ, organ system, or disease group.
Panels or profile tests allow for what?
Lots of tests at low costs, they help with pattern recognition.
What is the problem with panels or profile tests?
Each test adds an increased probability of an increased number of abnormal test results in healthy patients.
