What is the best approach when pretest probability is high?

• A. Treat without testing
• B. Obtain lumbar puncture before treatment
• C. Run a broad battery of tests
• D. Defer treatment until confirmatory testing

Answer: (A)

When the likelihood of disease is already high before testing, the priority is to treat rather than wait for confirmatory results. Acting promptly with empiric therapy helps prevent progression and improves outcomes, especially in time-sensitive conditions. Tests and procedures can be done in parallel to confirm the diagnosis and fine-tune treatment, but delaying therapy to obtain additional testing rarely improves the overall outcome and can worsen it. In contrast, delaying treatment until confirmatory testing is completed risks missing the narrow window where intervention is most effective. Lumbar puncture or other diagnostics are valuable for confirmation and guiding later management, but they should not block urgent treatment when the pretest probability is high.