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Table 1 Winthrop-University Hospital Infectious Disease Division's diagnostic weighted point system for diagnosing Legionnaires' disease in adults (modified [15])

From: Respiratory failure presenting in H1N1 influenza with Legionnaires disease: two case reports

Presentation Point score
Clinical features  
Temperature > 102 F* With relative bradycardia 5
Headache Active onset 2
Mental confusion/lethargy* Not drug-induced 4
Ear pain Acute onset 3
Nonexudative pharyngitis Acute onset 3
Hoarseness Acute not chronic 3
Sputum (purulent) Excluding AECB 3
Hemoptysis* Mild/moderate 3
Chest pain (pleuritic) 3
Loose stools/watery diarrhea* Not drug-induced 3
Abdominal pain* With/without diarrhea 2
Renal failure* Acute (not chronic) 3
Shock/hypotension* Excluding cardiac/pulmonary causes 5
Splenomegaly Excluding non-CAP causes 5
Lack of response to B-lactam antibiotics after 72 hours (excluding viral pneumonias) 5
Laboratory tests  
Chest x-ray Rapidly progressive asymmetric infiltrates* (excluding severe influenza (human, avian, swine), HPS, SARS) 3
Severe hypoxemia with (A-a gradient (> 35)* Acute onset 2
Hyponatremia* Acute onset 1
Hypophosphatemia Acute onset 5
Elevated SGOT/SGPT (early/mild/transient)* Acute onset 2
Elevated Total bilirubin Acute onset 1
Elevated LDH (> 400)* Acute onset 5
Elevated CPK* Acute onset 4
Elevated CRP* Acute onset 5
Elevated Cold agglutinin titers (1:64) Acute onset 5
Relative lymphopenia (< 21%)* Acute onset 5
Elevated Ferritin (> 2 n)* 5
Microscopic hematuria* Excluding trauma, BPH, Foley catheter, bladder and/or renal neoplasms 2
Total point score Legionnaires' Disease very likely > 15
Legionnaires' Disease likely 5-15
Legionnaires' Disease unlikely < 5
  1. AECB, acute exacerbation of chronic bronchitis; BPH, benign prostatic hyperplasia; CPK, creatine phosphokinase; CRP, C-reactive protein; HPS, Hantavirus pulmonary syndrome; LDH, lactate dehydrogenase; SARS, severe acute respiratory syndrome; SGOT/SGPT, serum glutamate oxaloacetate transaminase/serum glutamate pyruvate transaminase; *otherwise unexplained (acute and associated with the pneumonia).