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Updated: Nov 29, 2025
Rapid Molecular Detection and Differentiation of Influenza Viruses A and B
Published on: January 30, 2017
Clinical usefulness of a rapid molecular assay, ID NOW™ influenza A & B 2, in adults
Keiko Mitamura1, Masahiko Yamazaki2, Masataka Ichikawa3
1Eiju General Hospital, Taito-ku, Tokyo, 110-8645, Japan.
Introduction:
ID NOW™ Influenza A & B 2 (ID NOW 2) is a rapid molecular assay that combines two characteristics, namely the rapidness of rapid antigen detection test (RADT) and the high sensitivity of molecular assay.
Methods:
The clinical performance of ID NOW 2 compared with real-time RT-PCR was evaluated in adults.
Results:
The sensitivity of ID NOW 2 over multiple seasons from 2016/2017 to 2019/2020 was 97.3% (95% CI: 90.7-99.7) for Type A, 100% (95% CI: 81.9-100) for Type B, and 97.8% (95% CI: 92.2-99.7) for influenza (Type A + Type B), and it was significantly higher than the sensitivity of RADT, which was 80.0% (95% CI: 69.2-88.4) for Type A, 73.3% (95% CI: 44.9-92.2) for Type B, and 78.9% (95% CI: 69.0-86.8) for influenza. The sensitivity of RADT tended to be lower in patients in the particularly early period, within 12 h from disease onset; however, the sensitivity of ID NOW 2 remained high, increasing the difference between the sensitivity of RADT and ID NOW 2. The viral loads were low within 12 h from onset, and it was considered this affected the sensitivity of RADT due to its low analytical sensitivity. The specificity of ID NOW 2 was 98% or greater in all groups.
Conclusions:
Since ID NOW 2 has a high sensitivity and specificity in adults, it is anticipated to be used in clinical practice, particularly in patients who require early and accurate diagnosis.
