Rotavirus and adenovirus detecting method: sensitivity and specificity of rapid antigen testing: prospective study in one region of Ireland

Rotavirus and Adenovirus are common causes of gastroenteritis in children younger than 3 years worldwide. Rapid Antigen Testing (RAT) is a quick and easy tool to detect virus antigen in stool samples and is more specific than sensitive (higher specificity and lesser sensitivity). Reverse transcription-polymerase chain reaction (RT-PCR) and PCR are more sensitive and specific than RAT. Sensitive and specific tools are required for true diagnosis. We aim to determine sensitivity and specificity of RAT versus PCR testing of rotavirus and adenovirus. From November 18th 2016 to November 18th 2017, all children up to 3 years of age who presented to Mayo University Hospital with vomiting and diarrhoea had their stool tested for rotavirus and adenovirus by RAT in Galway University Hospital Laboratory (GUHL) and by PCR testing in the National Virus Reference Laboratory (NVRL) in Dublin; 143 stool samples were tested for Adenovirus, 126 (88%) tested negative at NVRL, two false positive at GUHL, specificity (98.5%). Seventeen were adenovirus positive in the NVRL, two false negative in GUHL, sensitivity (88%); 144 samples were tested for rotavirus, 108 (75%) were RV negative in the NVRL, one false positive at GUHL, specificity (99%); 36 samples were rotavirus positive in the NVRL, ten (28%) false negative in GUHL, sensitivity (72%). RAT has higher specificity than sensitivity and may be useful for mass screening at times of rotavirus or adenovirus outbreaks. PCR remains more sensitive and specific than RAT and is still required for true diagnosis.

Introduction

Detection of virus genome using real time reverse transcription-polymerase chain reaction (RT-PCR) is more sensitive and specific than Rapid Antigen Testing (RAT) and comprised of amplification of certain regions of the genome of the virus followed by identification of the genotype by fragment size analysis using electrophoresis [1–3]. RAT—as RV detecting tool—is more specific than sensitive (higher specificity and lesser sensitivity) [4–6]. RAT is a quick and easy tool to detect virus antigen in stool samples using immunochromatography and may be useful for investigating and screening group A rotavirus (RV) during outbreaks of food-borne and person-to-person transmitted gastroenteritis(GE). [5] This rapid diagnostic test is easy to perform at the bedside, as it takes only 20 min to reach a diagnosis with a simple procedure, and does not require special equipments. [5] Of 71 samples that were positive for RV by RT-PCR, 69, 68 and 63 were also recognised by RAT kits, indicating 97.2, 95.8 and 88.7% sensitivity for RAT kits, with only one false positive result in one of the three RAT kits (specificity up to 100%). [5]

When comparing the sensitivity of RAT for group A RV detection, it is clearly demonstrated that among various immunochromatography kits, sensitivity and specificity for group A RV infection were a bit different. In addition, it was observed that several RV genotypes G1, G3 and G9 were reacted with these kits. Therefore, genotype variations of RV may not be a problem for false negative results. [5]

RT-PCR assay was found to be specific to RV and broadly reactive to RV genogroups 1–4, 9, 10 and 12. [3] Specificity testing did not identify any cross-reactivity of the assay with a panel of 36 non-RV enteric virus specimens. [3]

Highly sensitive and specific methods such as one-step RT-PCR are still required for true diagnosis of viral GE following clinical suspicion of GE and GE associated complications and for RV vaccine efficacy trials. [1–3].