Important Variables Affecting Interpretation Of Lab Results Flashcards Preview

Pathology-IMED4111 > Important Variables Affecting Interpretation Of Lab Results > Flashcards

Flashcards in Important Variables Affecting Interpretation Of Lab Results Deck (10):
1

What are examples of analytical errors

Lab equipment malfunction, failure to detect shifts/drifts in quality control, sample mix up, sample contamination

2

What are examples of post analytical errors

Errors in validation, transcription error, failure in reporting/interpretation of result, excessive turnaround, delay in acting on results

3

Define sensitivity in setting of diagnostic testing

Proportion of people who have positive test and the disease divided by people with the disease

4

Define specificity in setting of diagnostic testing

Proportion of people who have negative test and do not have the disease over people without the disease

5

Define PPV of a test

Positive predictive value - number of people with a positive test who have the disease divided by the number of people with a positive test

6

Define NPV of a test

Negative predictive value - number of people with a negative test who do not have disease divided by those with a negative test

7

How does disease prevalence effect PPV and NPV values of a test

As prevalence increases, PPV increases and NPV decreases

8

How can normal ranges be determined (hint reference limits and intervals)

Using reference limits - value where it is expected that stated population of patients will have values over or under that value
And reference intervals - space between two reference limits

Eg 95% RI is interval between the RL at 2.5% and RL at 97.5%

9

What are some examples of sub populations that have different reference limits/intervals

Male versus female
Children versus adults
Ethnicity
Healthy versus unhealthy

10

What are examples of pre analytical errors

Wrong tests requested, blood sampled from IV lines, delayed separation of components, temperature, wrong tube/incorrectly filled, labeling errors , wrong patient

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