2087. Comparison of AlereTM i Influenza Flu A &B 2 and Cobas® Influenza A/B nucleic acid amplification tests for detection of Influenza A/B in nasopharyngeal swabs collected from children
Session: Poster Abstract Session: Diagnostics: Virology
Saturday, October 6, 2018
Room: S Poster Hall
Background: Early diagnosis of influenza virus is critical for patient management and infection control. Both, Alere™ i Influenza A &B 2 assay (Alere i; Abbott Laboratories) and Cobas® Influenza A/B nucleic acid test (LIAT; Roche Molecular Systems Inc.) are rapid sample-to-answer CLIA waived molecular assays for flu detection. The aim of this study was to compare the performance of these two commercially available flu assays.

Methods: A total of 201 children <18 years were prospectively enrolled from January to April 2018. Subjects with a physician’s test order of Flu test were considered eligible for study participation. Nasopharyngeal swab specimens were obtained after consenting the subjects. Aliquots made were frozen for testing on different diagnostic platforms per manufacturer’s instructions. CDC Flu A/B PCR was used as a reference method to evaluate the performance of the two platforms.

Results: Among the 201 specimens tested, CDC PCR detected Flu A/B in 107 samples (Flu A: 73, Flu B: 36; Dual flu A/B positive: 2), while Alere i assay detected 102 samples (Flu A: 69, Flu B: 37; Dual flu A/B positive: 4; Invalid rate: 1/201-0.5%) and LIAT assay detected 112 samples (Flu A: 74, Flu B: 38; Invalid rate: 11/201-5.5%). The overall sensitivities for Alere i vs LIAT (95.3% vs 100%) and specificities (100% vs 94.7%) were comparable. Alere i assay missed 5 samples detected by CDC PCR at high Ct values of 33.81 (range 31.75 to 36.04). Standard of care BD Veritor™ Flu A/B antigen test (BD) had a sensitivity and specificity of 77.6% (68.3-84.8) and 98.9% (93.3-99.9).

Conclusion: The diagnostic performance for Alere™ i and LIAT flu assays were found comparable. Both molecular assays had >17% higher sensitivity than BD veritor antigen test. LIAT assay was found to be more sensitive than Alere i whereas Alere i had greater specificity than LIAT.

Table 1: Alere i and LIAT assay results versus CDC Flu A/B PCR PCR

Assay

Target

True positive

False positive

True negative

False Negative

Sensitivity

% (range)

Specificity

% (range)

Alere i

Flu A

68

1

127

5

93.2 (84.1-97.5)

99.2 (95.1-100.0)

Flu B

35

2

163

1

97.2 (83.8-99.9)

98.8 (95.2-99.8)

Overall

102

0

94

5

95.3 (88.9-98.3)

100 (95.1-100)

LIAT

Flu A

73

1

127

0

100 (93.8-100)

99.2 (95.1-100.0)

Flu B

34

4

161

2

94.4 (80.0-99.0)

97.6 (93.5-99.2)

Overall

107

5

89

0

100 (95.7-100)

94.7 (87.5-98.0)

Neena Kanwar, PhD1, Jeffrey Michael, DO2, Kathryn Doran, DO3, Emily Montgomery, MD3 and Rangaraj Selvarangan, PhD4, (1)Children's Mercy Hospital, Kansas City, MO, (2)Emergency Medicine, Children's Mercy Kansas City, Kansas City, MO, (3)Children's Mercy Hospital and Clinics, Kansas City, MO, (4)Microbiology Laboratory, Children's Mercy Hospital and Clinics, Kansas City, MO

Disclosures:

N. Kanwar, Alere Inc.: Collaborator , Research grant .

J. Michael, None

K. Doran, None

E. Montgomery, None

R. Selvarangan, Abbott Diagnostics: Investigator , Research grant .

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