Evaluation of Indirect Fluorescent Antibody Assays Compared to Rapid Influenza Diagnostic Tests for the Detection of Pandemic Influenza A (H1N1) pdm09

Abstract

Performance of indirect fluorescent antibody (IFA) assays and rapid influenza diagnostic tests (RIDT) during the 2009 H1N1 pandemic was evaluated, along with the relative effects of age and illness severity on test accuracy. Clinicians and laboratories submitted specimens on patients with respiratory illness to public health from April to mid October 2009 for polymerase chain reaction (PCR) testing as part of pandemic H1N1 surveillance efforts in Orange County, CA; IFA and RIDT were performed in clinical settings. Sensitivity and specificity for detection of the 2009 pandemic H1N1 strain, now officially named influenza A(H1N1)pdm09, were calculated for 638 specimens. Overall, approximately 30% of IFA tests and RIDTs tested by PCR were falsely negative (sensitivity 71% and 69%, respectively). Sensitivity of RIDT ranged from 45% to 84% depending on severity and age of patients. In hospitalized children, sensitivity of IFA (75%) was similar to RIDT (84%). Specificity of tests performed on hospitalized children was 94% for IFA and 80% for RIDT. Overall sensitivity of RIDT in this study was comparable to previously published studies on pandemic H1N1 influenza and sensitivity of IFA was similar to what has been reported in children for seasonal influenza. Both diagnostic tests produced a high number of false negatives and should not be used to rule out influenza infection.

Clinical Investigations. Comparison of Directigen Flu A+B with Real Time PCR in the Diagnosis of Influenza / Сравнение Иммунохроматографического Метода (Directigen Flu A+B) И Теста RT-PCR При Инфекциях Гриппа

“…That is comparable to previously published studies for rapid tests, including the Directigen Flu A+B. 5,14,15 The overall sensitivity of Directigen Flu A+B in the present study using combined nose and throat swabs is 48.5% for infl uenza A and 13.3% for infl uenza B which is lower than what has been found in other studies. In general, rapid tests show lower sensitivity than the sensitivity of PCR.…”

“…Many studies have demonstrated that early initiation of oral oseltamivir therapy increased its therapeutic effects reducing the duration of the symptoms, severity of the illness, incidence of secondary complications, and duration of the hospitalization. [3][4][5] Infl uenza can be diffi cult to diagnose based on clinical signs and symptoms alone because infl uenza illness can be similar to illness caused by other infectious agents including parainfl uenza viruses, adenovirus, respiratory syncytial virus and Legionella spp. 1,2,6 Timely diagnosis and treatment of patients with infl uenza is the reason why physicians need rapid infl uenza diagnostic tests with high sensitivity requiring no complex lab equipment and being able to be performed and interpreted easily within 15 minutes.…”

A diagnostic one-step real-time reverse transcription polymerase chain reaction method for accurate detection of influenza virus type A

“…It was reported that the sensitivity of the rapid influenza diagnostic test (RIDT) for the detection of influenza A (H1N1) pdm09 varied between 18% and 69%. The sensitivity results for DFA were also different and ranged from 47% to 93% [34–36]. In the present study, a great similarity was observed between the results of the conventional methods (culture and DFA), our designed assay and those of the WHO.…”

Diagnosing Viral and Atypical Pathogens in the Setting of Community-Acquired Pneumonia

“…Complicating the assessment of the usefulness of these assays is that the performance seems to vary between influenza strains and, unfortunately, during the H1N1 09 pandemic they were less than optimal. [43][44][45][46][47] A recent metaanalysis of 159 published studies of rapid influenza tests found the pooled sensitivity, sensitivity, specificity, and positive and negative predictive values to be 62%, 98%, 34%, and 38%, respectively. 47 Not surprisingly, given these data, there is little evidence that rapid influenza tests are currently used by clinicians to alter patient management.…”