Guideline for the Prevention and Control of Norovirus Gastroenteritis Outbreaks in Healthcare Settings, 2011

Q2: What are the best methods to identify a norovirus outbreak in a healthcare setting?

Diagnostic methods – Fecal specimens

EM

Author, Yr (Ref)	Study Design Quality	Study Objective	Population and Setting N	Results	Comments	Ref ID_Data extracted by
Rabenau, H; 2003 17	Diagnostic study   1, 2	To compare the sensitivity and specificity of: 1. ELISA when compared with a) TEM and PCR or b) PCR only 2. TEM when compared with a) ELISA and PCR or b) PCR only	Inhabitants and employees of homes for the elderly (in Frankfurt, Germany) aged 20 to >60 years; 73% females, 42% > 60 yrs.   244 stool samples from 227 patients	Test characteristics (%) for ELISA When compared with TEM and PCR Sensitivity – 50.0 Specificity – 96.2 PPV – 68.0 NPV – 92.2 (True Positive[TP] – 17; True Negative[TN] – 202; FP – 8; FN – 17) When compared with PCR only Sensitivity – 31.3 Specificity – 94.9 PPV – 60.0 NPV – 84.9 (TP – 15; TN – 186; FP – 10; FN – 33)   Test characteristics (%) for TEM When compared with ELISA and PCR Sensitivity – 88.2 Specificity – 99.0 PPV – 93.8 NPV – 98.1 (TP – 30; TN – 208; FP – 2; FN – 4) When compared with PCR only Sensitivity – 58.3 Specificity – 98.0 PPV – 87.5 NPV – 90.6 (TP – 28; TN – 192; FP – 4; FN – 20)   Test characteristics (%) for PCR When compared with ELISA and TEM Sensitivity – 94.1 Specificity – 92.4 PPV – 66.7 NPV – 99.0 (TP – 32; TN – 194; FP – 16; FN – 2)	Power and sample size not reported.   Prevalence not reported	801_RA
Richards, A; 2003 119	Diagnostic Study   1,2	To determine the test characteristics of ELISA and EM in detecting norwalk-like virus (NLV) infection when compared with PCR	Fecal samples collected from patients involved in outbreaks of gastroenteritis in the UK   531 fecal samples	Test characteristics (%) of ELISA vs. PCR Sensitivity – 55.5(51.1-60.0) Specificity – 98.3(97.1-99.9) PPV – 95.0(CI not reported) NPV – 76.9 (CI not reported)   Test characteristics (%) of EM vs. PCR Sensitivity – 23.9(19.5-28.1) Specificity – 99.2(98.3-100) PPV – 93.9(CI not reported) NPV – 70.7(CI not reported)   Identification of NLV as the cause of an outbreak (% of outbreaks) When the causative agent was defined by ≥ 2 positive samples EM – 7.2 ELISA – 18.6 PCR – 41.5 When the causative agent was defined by ≥ 1 positive samples EM – 19.6 ELISA – 47.8 PCR – 62.8   Sensitivity; Specificity of ELISA based on number of samples collected 2 samples – 52.9; 100 ≥4 – 69.2; 100 ≥6 – 71.4; 100   Other results Agreement between ELISA and PCR – 81.8% (Kappa = 0.57) Sensitivity of ELISA was significantly increased when compared with EM (P<0.01)	Power and sample size not reported.   Prevalence not reported	848_RA

Next Table