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POCT impact on disease diagnosis and surveillance Vitali Sintchenko Marie Bashir Institute for Emerging Infectious Diseases & Biosecurity
POCT impact on disease diagnosis and surveillance
Vitali Sintchenko
Marie Bashir Institute
for
Emerging
Infectious Diseases
&
Biosecurity
Concept of POCT is not new
Concept of POCT is not new
Gartner’s Hype Cycle
POCT for Bacterial Infections
icpmrCentre for Infectious Diseases and Microbiology, Westmead Hospital
• Purpose• To inform effective and proportional antimicrobial
therapy by distinguishing viral from bacterial infection
• To inform patient management and infection control
• Desired characteristics• Ability to detect important pathogens accurately
• Robustness and rapidity (<1h)
• Simplicity in operation/Equipment-free
• Low cost
POCT for bacterial RTIs
Assay Time to
result
Technology Target Analytical
performance
Cepheid Xpert 1-2h Real-time PCR, MSSA, MRSA, C.
difficile, GBS, MTB
99% sens;
70-90% spec
Biofire
Filmarray
1h Nested PCR B. pertussis;
M. pneumoniae,
C.pneumoniae
84-99% sens;
98-100% spec
Curetis
Unyvero
4h Multiplex PCR with
hybridisation to probes
spotted on membrane
arrays
Multiple bacteria
and 22 antibiotic
resistance genes
50-100% sens;
72-100% spec
Legionella
urinary antigen
15min –
4h
Immuno-
chromatography or
sandwich ELISA
Legionella
pneumophila
serogroup 1
78-97% sens;
95% spec
S. pneumoniae
urinary antigen
15min –
4h
Immuno-
chromatography or
sandwich ELISA
Different serotypes
of S.pneumoniae
52-78% sens;
90% spec
Zumla et al. Lancet Inf Dis 2014;14:1123
POCT for bacterial RTIs
Assay Time to
result
Technology Target Analytical
performance
Cepheid Xpert 1-2h Real-time PCR, MSSA, MRSA, C.
difficile, GBS, MTB
99% sens;
70-90% spec
Biofire
Filmarray
1h Nested PCR B. pertussis;
M. pneumoniae,
C.pneumoniae
84-99% sens;
98-100% spec
Curetis
Unyvero
4h Multiplex PCR with
hybridisation to probes
spotted on membrane
arrays
18 bacteria and 22
antibiotic resistance
genes
50-100% sens;
72-100% spec
Legionella
urinary antigen
15min –
4h
Immuno-
chromatography or
sandwich ELISA
Legionella
pneumophila
serogroup 1
78-97% sens;
95% spec
S. pneumoniae
urinary antigen
15min –
4h
Immuno-
chromatography or
sandwich ELISA
Different serotypes
of S.pneumoniae
52-78% sens;
90% spec
Zumla et al. Lancet Inf Dis 2014;14:1123
The use of Pneumococcal urinary antigen increased percentage of
patients with etiologic diagnosis from 39% to 53% and the relative
frequency of pneumococcal pneumonia from 6% to 19%
(Gutierez et al. CID 2003;36:286)
Impact on CAP and HAP
Jamal et al. JCM 2014:52:2487
Fully integrated system
Boehme et al. NEJM 2010;363:1005
XpertMTB/RIF
Potential impact
Courtesy of C Gilpin
Proportion of TB cases detected and time to detection
POCT for bacterial UTIs
Technology Time to
result
Bacteria in urine Detection
limit
Pretreatment
Micro-fabricated
electrode assay
45 min E.coli
K.pneumoniae
P.mirabilis
Pseudomonas sp
Enterococcus sp
106-108 CFU/mL Lysis
Microfluidic
FRET-ISH
30 min E. coli 102 CFU/mL Centrifuge and
dilution
PCR/LAMP on
a chip
1h E. coli
Staphylococcus sp
Enterococci sp
102 CFU/mL Automated
washing on chip
Microfluidic
fluorescence
assay
30 min E. coli 50 CFU/mL Filtering
Cho et al. Biosens Bioelectronics 2015;74:601
Multi-channel paper microfluidic chip
• Chip is preloaded with polyclonal Ab-
conjugated particles
• Sample is loaded onto the inlet that flows
through each channel
• Immunoagglutination increases light
scattering which is captured by an
iPhone
POCT for bacterial STIs
Technology Time to result Sample type Performance
Biostar Optical
immunoassay
30min Cervical/ Male urine 60-73% sens; 98-100% spec
Chlamydia Rapid
Test
30min Vaginal/Male urine 41-74% sens; 89-95% spec
Xpert CT/NG 1h Cervical/Vaginal/Urine 97-99% sens; 99% spec
Technology Time to
result
Sample type Performance
Biostar OIA 30min Cervical 60% sens; 90% spec
PATH GC-Check 30min Vaginal/Cervical 54-70% sens; 89-98% spec
Xpert CT/NG 1h Cervical/Vaginal/Urine 95-99% sens; 99% spec
Chlamydia trachomatis
Neisseria gonorrhoeae
POCT for syphilis
Immunochromatography assay using
recombinant TP, 15kDa, 17 kDa antigens
POCT for syphilis
Bristow et al. Sexual Health 2015;12:119
Public health benefits and challenges
• [Expected] Benefits• Increase in laboratory-confirmed diagnoses
• Increased uptake and timeliness of treatment
• Reduction of duration of infectiousness
• Reduction in prevalence (with high enough coverage
of testing), especially among hard-to-reach groups
• Challenges• Prevalence and test performance - Potentially
missed/misdiagnosed cases
• Potential reduction of completeness of notification
data
• Monitoring of antibiotic resistance
Greatest impact in high prevalence areas
Hui et al. Sexual Health 2013;10:348
2% and 3% reduction of prevalence of NG and CT with 44%
coverage of annual screening
Concluding remarks
• POCT is becoming a reliable and cost-effective
supplement to established laboratory diagnostics,
which can be used in the clinic and outreach and help
to ensure equity in healthcare provision
• Clinical trials to evaluate performance of POCT and to
remove barriers to testing are critical
• Public health implications of POCT for diseases with
epidemic potential can be significant and should be
taken into account when implementation of new
technology is planned
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