5 Selecting and Interpreting Investigations Free Online FlashCards

What should you clarify before ordering an investigation?

State the suspected condition and the decision each possible result would inform, such as diagnosis, triage, monitoring, or treatment.

When is an investigation likely to have limited value?

A test has limited value if its result will not change management, follow-up, or a meaningful discussion with the patient.

How should testing be handled when a patient is unstable?

For an unstable patient or time-critical threat, begin stabilization and necessary treatment promptly; obtain tests in parallel when feasible.

What is a key trade-off of rapid bedside tests?

A rapid bedside test may answer an urgent question, but it may be less definitive than confirmatory testing.

What expected impact should you consider before testing?

Consider whether results could alter treatment, disposition, monitoring, or the need for further investigation.

Name two possible downstream harms of testing.

False results or incidental findings may trigger repeat tests, invasive procedures, anxiety, or treatment that offers no benefit.

How do you estimate pretest probability?

Estimate it from the patient's history, examination, risk factors, and relevant background rates.

What does test sensitivity describe?

Sensitivity is how often a test is positive when the condition is present.

What does test specificity describe?

Specificity is how often a test is negative when the condition is absent.

Why can a positive result be misleading when disease is uncommon?

When the condition is uncommon, false positives can outnumber true positives even with a reasonably accurate test.

In the 1% probability example, about what share of positive results are true positives?

With a 1% condition probability and 90% sensitivity and specificity, about 9 of 108 positive results are true positives—roughly 8%.

What context matters when interpreting a test result?

Interpret results alongside the patient's presentation, the test's intended use, and its limitations; check validity, timing, and specimen quality.