Pediatric Emergency Playbook

Does Your Patient Have Streptococcal Pharyngitis? No Problem -- I'll just Swab. Not So Fast...   Fagan Nomogram for Likelihood Ratios 1. Decide on your pre-test probability of the disease (choose an approximate probability based on our assessment) 2. Use the likelihood ratio that correlates to your exam. 3. Draw a straight line frm your pre-test probability starting point, to the LR of the feauture/test, take it through to find your post-test probability 4. Use this new post-test probability to help in your decision Your patient has palatal petechiae, which confers a positive likelihood ratio (LR+) of 2.7 See below how to use this statistic based on your clinical assessment" Low Probability Moderate Probability High Probability   List of Likelihood Ratios for Streptococcal Pharyngitis Symptoms and signs Positive LR (95% CI) Negative LR (95% CI) Sensitivity (95% CI) Specificity (95% CI) Scarlatiniform rash 3.91 (2.00-7.62) 0.94 (0.90-0.97) 0.08 (0.05-0.14) 0.98 (0.95-0.99) Pala