Laboratory QA
Multiplex Viral Polymerase Chain Reaction
Testing Using the FilmArray Device Compared
With Direct Fluorescent Antibody Testing
Jason Wang, MD,1 Debra B. Simons, MT(ASCP),2 James L. Adams, MS, MT(ASCP),2
Robert C. Jerris, PhD,1,2 Beverly Barton Rogers, MD1,2*
ABSTRACT
Advances in fluidics, electronics, and instrument design have enabled
automation of complex molecular assays. The FilmArray Respiratory
Panel (RP) is one such assay; it allows for rapid detection of multiple
viral and bacterial respiratory targets via nested polymerase chain
reaction (PCR), with all components contained within a single pouch.
We performed a detailed comparison of workflow between the
FilmArray RP and direct fluorescent antibody (DFA) staining. The
FilmArray RP proved to be more efficient, with as few as 91 total
touches needed and as little as 4 minutes 52 seconds hands-on time.
Laboratory testing for upper respiratory infections most
commonly includes identification of pathogens using rapid
antigen testing, direct fluorescent antibody (DFA) testing
with or without culture, and polymerase chain reaction
(PCR) systems that identify single or multiple pathogens.1-4
The complexity varies among the methods; however, all
methods other than some rapid antigen tests are identified
as high complexity. The FilmArray Respiratory Panel (RP)
(BioFire Diagnostics, Inc., Salt Lake City, UT), classified
by the United States Food and Drug Administration (FDA)
as moderate complexity, is the first PCR-based assay for
respiratory pathogens that combines ease of use with multiplex PCR testing for 17 respiratory viral pathogens and 3
DOI: 10.1309/LMOMIXQ6N4JAPDX1
Abbreviations
DFA, direct fluorescent antibody; PCR, polymerase chain reaction;
RP, Respiratory Panel; CLIA, Clinical Laboratory and Improvement
Amendments; FDA, United States Food and Drug Administration; TAT,
turnaround time
Department of Pathology, Emory University School of Medicine1 and
Department of Pathology, Children’s Healthcare of Atlanta2, Atlanta,
Georgia
*To whom correspondence should be addressed.
E-mail: [email protected]
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This compares with as many as 502 total touches and 12 minutes
45 seconds hands-on time for DFA staining. FilmArray RP detected
a greater number of organisms (20 viruses and bacteria vs 7 viruses
for DFA staining) and required less training compared with DFA
staining. The ease of use of the FilmArray RP makes this molecular
assay amenable to operation 24 hours a day, 7 days a week in routine
laboratory and point-of-care settings.
Keywords: FilmArray, PCR, Lean, DFA test, rapid antigen testing,
respiratory panel
respiratory bacterial pathogens that have been cleared for
testing by the FDA.5 The purpose of this study is to perform a detailed workflow analysis of the FilmArray RP with
DFA testing, a method that is currently in use in many laboratories, for the detection of respiratory viruses.
Materials and Methods
To assess complexity, we used methods from the field of
lean manufacturing. The goal of any production process
is to move the product through the required steps with
no interruptions or waiting between steps. The number of
interruptions and amount of waiting are more responsible
than the number of steps for diminishing the efficiency
and ease of work. In this study, with no product movement
between different workstations, the process workflow
was evaluated by measuring the equivalent of product
movement via the tasks, steps, and touches performed
by the operators.6 Operator analysis for the FilmArray RP
involved video recording the training given to 3 medical
technologists who were unfamiliar with the instrument.
Technologist training involved one-on-one instruction and
included a demonstration of test performance and instrument use. Each medical technologist tested 3 specimens,
and all of the activities related to processing, running, and
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Laboratory QA
providing results for the samples were recorded on digital
media, which was later viewed to document the number
of steps and touches needed to achieve a result. A step
was defined as a discrete group of actions associated with
processing, running, or reporting results; these activities
included putting on gloves, unwrapping a syringe, and
printing the results. A touch was defined as the number
of times the technologist actually touched an object; each
step was typically comprised of more than 1 touch. The
amount of hands-on time was measured and documented.
Operator analysis for the DFA test (D3UltraDFA Respiratory
Virus ID Kit, Quidel Corporation, San Diego, CA) involved
recording 3 different technologists performing the DFA test
using 3 samples each, run individually to mirror the singlepiece flow of the FilmArray RP. These technologists were
experienced in running the DFA test; extensive training is
necessary to perform and interpret the test. Activities were
recorded by digital media, and the hands-on time and the
numbers of steps and touches were counted.
Results
The number of operator steps using the FilmArray RP was
32 per operator. The DFA test required 23 steps for nonmucoid specimens and 26 steps for mucoid specimens;
the latter specimen type requires additional rinse and centrifugation steps. Using the first run for each technologist,
the total number of touches using the FilmArray RP was
117 for operator A, 100 for operator B, and 91 for operator C, with hands-on times of 8 minutes, 12 minutes 41
Table 1. Total Number of Touches, FilmArray
RP vs DFA
Total Touches, No.
Method
FilmArray RPaDFAb
Operator
ABCD E F
Run 1
11710091 299 330c502c
Run 2
11012596 303 313 492c
Run 3
112
97
101 303
361c477
Average, operator
11310796 302 335 490
Average, method 105
376
RP, Respiratory Panel; DFA, direct fluorescent antibody.
a
BioFire Diagnostics, Inc., Salt Lake City, UT.
b
D3UltraDFA Respiratory Virus ID Kit, Quidel Corporation, San Diego, CA.
c
Mucoid samples, which require additional rinsing and centrifugation.
seconds, and 5 minutes 31 seconds for operators A, B,
and C, respectively. No improvement was observed in the
number of touches and the hands-on time for each technologist with repeated runs, indicating that minimal training
was sufficient to perform at the optimal level, even on the
first run (Table 1 and Table 2). The turnaround time (TAT),
defined as hands-on time + run time (1 hour 3 minutes), for
the FilmArray RP on the first run ranged from 1 hour 8 minutes 31 seconds to 1 hour 15 minutes 41 seconds.
Although the DFA test required fewer steps than the
FilmArray RP, the average number of touches for the DFA
test was 376 (range = 299 to 502 touches), more than
3-fold as many as for the FilmArray system (average = 105
touches), indicating a greater number of touches per step
Table 2. Summary of Total Hands-on Time, FilmArray RP vs DFA
Total Hands-on Time
Method
FilmArray RPaDFAb
OperatorA
Run 1
Run 2
Run 3
Average, operator
Average, method
B
C
8 min
12 min 41 s
5 min 31 s
8 min 5 s
9 min 28 s
4 min 52 s
7 min 19 s
10 min 19 s
5 min 20 s
7 min 47 s
10 min 49 s
5 min 14 s
7 min 57 s
D
E
F
12 min 59 s
11 min 35 s
11 min 26 s
12 min
12 min 8 s
14 min 8 sc
11 min 15 s
10 min 34 sc
11 min 56 s
11 min 57 sc
12 min 45 sc
12 min 39 s
12 min 27 s
RP, Respiratory Panel; DFA, direct fluorescent antibody.
a
BioFire Diagnostics, Inc., Salt Lake City, UT.
b
D3UltraDFA Respiratory Virus ID Kit, Quidel Corporation, San Diego, CA.
c
Mucoid samples, which require additional rinse and centrifugation steps.
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Winter 2014 | Volume 45, Number 1 Lab Medicine
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Laboratory QA
(Table 1). The average hands-on time for the DFA test was
12 minutes 8 seconds, more than 4 minutes longer than
the average hands-on time of 7 minutes 57 seconds for
the FilmArray RP (Table 2). The DFA test TAT of nasopharyngeal specimens (including hands-on time, slide preparation, drying time, staining, and interpretation) is 2 hours
40 minutes, compared to approximately 1 hour 15 minutes
for the FilmArray RP.
The FilmArray instrument further simplifies respiratory viral
testing by making it possible to move previously highly
complex testing into the routine clinical laboratory, or perhaps even to the point of care (if achievable while abiding
by state laws). The BioFire Diagnostics FilmArray combines
multiplex PCR testing, including the analytical sensitivity
and specificity expected of a PCR assay, with ease of use
and 1-hour turnaround time. This enables sensitive, specific, and rapid detection of 20 respiratory pathogens. LM
Acknowledgments
Discussion
The choice of a laboratory test should always be based
on clinical need. Within that context, quality, operational
simplicity, and cost are 3 primary considerations for a
laboratory test. This study assessed the operational simplicity of the FilmArray RP and the DFA test and showed
that the FilmArray is less complex, has less hands-on time,
and has a shorter TAT than the DFA test. The DFA method
used in this study identified 7 viral pathogens and yielded
a TAT of 2 hours 40 minutes, with a hands-on time averaging 12 minutes 8 seconds when evaluating a nasopharyngeal sample. By contrast, the FilmArray RP detected 20
respiratory pathogens and yielded a TAT of as little as 1
hour 7 minutes 52 seconds, with a hands-on time of as
little as 4 minutes 52 seconds. Simultaneous testing of
multiple specimens with the FilmArray RP requires multiple
instruments, whereas simultaneous testing of multiple DFA
specimens only requires additional time for specimen handling, slide preparation, and slide interpretation (approximately 5-10 minutes per additional specimen).
In addition to operational simplicity, the FilmArray RP
has also shown increased analytical sensitivity to detect
viral pathogens compared with the DFA test. Poritz et al7
compared the FilmArray RP multiplex PCR assay with
the DFA test (Light Diagnostics Simulfluor respiratory
screen, Millipore Corporation, Billerica, MA) and observed
a discordance in results for adenovirus, influenza B, and
parainfluenza 3 (P <.01); in each instance, the FilmArray
RP detected the presence of a virus load greater than 50%
more frequently than the DFA test.7 The same authors
also reported that FilmArray RP identified significantly
more pathogens and had fewer clinical samples with no
pathogen identified than the DFA test.7 The two tests still
showed a high concordance (positive percent agreement
ranging from 55%-100% with agreement greater than 90%
for most organisms compared).7
The authors acknowledge expert technical assistance from
Selome Tesfaye, Pam Bartlett, Cecilia Luther, Kathleen
Temple, Charles Ash, and Becky Deridder.
Conflicts of Interest
Dr. Rogers serves on an advisory board for BioFire Diagnostics. BioFire Diagnostics provided instrumentation and
reagents so this study could be performed.
References
1. Couturier MR, Barney T, Alger G, et al. Validation of the Idaho
Technology Inc. FilmArray Respiratory Panel for Clinical Use at
Primary Children’s Medical Center, Poster M60. Poster. 27th Annual
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6. Mann D. Creating a Lean Culture: Tools to Sustain Lean Conversions.
2nd ed. New York: Productivity Press/Taylor & Francis Group; 2010.
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