The Diagnostic Value of Serum C-Reactive Protein for Identifying Pneumonia in Hospitalized Patients with Acute Respiratory Symptoms

Table 3

Multilevel likelihood ratios for different serum C-reactive protein intervals.

Serum CRP; (mg/L)	Pneumonia; ()	Other lower respiratory tract infections; ()	LR+
>250	171	7	16.3 (7.7–34.4)
225–250	40	5	5.3 (2.1–13.4)
200–225	32	4	5.3 (1.9–15.0)
175–200	53	17	2.0 (1.2–3.5)
150–175	58	13	2.9 (1.6–5.3)
125–150	46	23	1.3 (0.8–2.1)
100–125	49	30	1.1 (0.7–1.6)
75–100	31	42	0.5 (0.3–0.7)
50–75	19	60	0.2 (0.1–0.3)
25–50	27	67	0.2 (0.1–0.4)
<25	20	98	0.1 (0.0–0.2)

CRP, C-reactive protein; LR, likelihood ratio.
Other lower respiratory tract infections included acute bronchitis and acute exacerbations of COPD.