| Literature DB >> 26367243 |
Gerald J Kost, William Ferguson1, Anh-Thu Truong1, Jackie Hoe1, Daisy Prom1, Arirat Banpavichit1, Surin Kongpila1.
Abstract
Ultrahigh sensitivity and specificity assays that detect Ebola virus disease or other highly contagious and deadly diseases quickly and successfully upstream in Spatial Care Paths™ can stop outbreaks from escalating into devastating epidemics ravaging communities locally and countries globally. Even had the WHO and CDC responded more quickly and not misjudged the dissemination of Ebola in West Africa and other world regions, mobile rapid diagnostics were, and still are, not readily available for immediate and definitive diagnosis, a stunning strategic flaw that needs correcting worldwide. This article strategizes point-of-care testing for diagnosis, triage, monitoring, recovery and stopping outbreaks in the USA and other countries; reviews Ebola molecular diagnostics, summarizes USA FDA emergency use authorizations and documents why they should not be stop-gaps; and reduces community risk from internal and external infectious disease threats by enabling public health at points of need.Entities:
Keywords: Ebola; Ebola diagnostic center; emergency use authorization; facilitated-access self-testing; point-of-care; public health resilience; ultrahigh sensitivity; ultrahigh specificity
Mesh:
Year: 2015 PMID: 26367243 PMCID: PMC7103715 DOI: 10.1586/14737159.2015.1079776
Source DB: PubMed Journal: Expert Rev Mol Diagn ISSN: 1473-7159 Impact factor: 5.225
WHO point-of-care target product profile.
| Priority | ||
| Target use setting | Decentralized health care facilities with no laboratories infrastructure available | Decentralized health care facilities with minimum laboratory infrastructures available. |
| Intended use | In Ebola outbreak setting, distinguish between symptomatic patients with acute Ebola virus infection and non-Ebola virus infection without the need for confirmatory testing | In Ebola outbreak setting, distinguish between symptomatic patients with acute Ebola virus infection and non-Ebola virus infection with the need for confirmatory testing |
| Clinical sensitivity†,‡ | >98% | >95% |
| Analytical specificity | >99% | >99% |
| Type of analysis | Qualitative or quantitative | Qualitative |
| Sample type | Capillary whole blood from finger stick once/if the use of this type of samples has been validated. Other less invasive sample types (e.g., saliva, buccal) once/if their use has also been validated | Whole blood from phlebotomy, in particular if collection is simple and automated to reduce biosafety requirements |
| Test procedure | ||
| Number of steps to be performed by operator (use of different reagents/incubation steps) | <3 | <10 |
| Biosafety§ | No additional biosafety in addition to PPE§ | No additional biosafety in addition to PPE§ |
| Need for operator to transfer a precise volume of sample | No | Acceptable if adequate disposable blood transfer device is provided |
| Time to result | <30 min | <3 h |
| Internal control | included | Included |
| Sample preparation | None or fully integrated | None or fully integrated |
| Operating conditions | 5–50°C | 5–40°C |
| Reagent storage (stability) | 24 months at 40°C + 90% RH; no cold chain should be
required. | 12 months at 30°C + 70% RH including 3 months at 40°C, no
cold chain should be required. |
| In use stability (under tropical conditions) | >1 h for single-use test after opening the pouch | >0.5 h for single-use test after opening the pouch |
| Reagents reconstitution | All reagents ready to use | Reconstitution acceptable if very simple to do.
|
| Training needs | Less than half a day for any level health care worker. Job aid provided. | Less than 2 days for any level of health care worker. Job aid provided. |
| Equipment (if needed) | Small and portable, handheld instrument | Small, table top device, portable |
| Power requirements | None required | 110–220 V AC current |
| Need for maintenance/spare parts | None | 1 annual calibration ideally by operator |
Detection should occur prior to presenting with fever to health care facilities in order to stop the spread of an outbreak.
†Clinical sensitivity in first 10 days of presentation. Allow for repeat testing as per WHO guidelines.
‡Reference test: Lab validated quantitative PCR assay on blood sample (whole blood or plasma) drawn by phlebotomy.
§Biosafety resources for Ebola [70,71].
The following organizations contributed to the development of this target Product Profile: WHO, MSF, FIND, BMGF, US DoD, US CDC, NIH, and PATH. Editorial comment regarding early detection to stop outbreaks in the target population added by the POCT•CTR.
PPE: Personal protective equipment.
Figure 1.The Ebola diagnostic center.
Point-of-care tests implemented for Ebola secured settings.
| 2A. Emory university hospital
specialized isolation area | ||
|---|---|---|
| Manufacturer website | Instrument | Tests/status |
| Abaxis | Piccolo Express | Chemistry profiles, Magnesium, Phosphate, liver enzyme assays, others available† |
| Instrumentation Laboratory | GEM Premier 4000 | pH, pC02, p02, Na+, K+, Ca++, Cl-, Glu, Lac, Hct, THb, CO-Oximetry, TBil |
| Siemens | CLINITEK Status | Albumin, Bilirubin, Cr, Glu, Ketone, Leukocytes, Nitrite, pH, Protein, Specific Gravity, Urobilinogen, others available‡ |
| Hoffman-La Roche | CoaguChek | PT/INR§ |
| Sysmex | pocH-100i | CBC: WBC (3-part differential), RBC, Hb, Hct, MCV, MCH, MCHC, Platelets¶ |
| Alere | BinaxNOW | Malaria |
| BioFire Diagnostics | FilmArray | Infectious diseases including Ebola |
†See [72] for test clusters.
‡See [73].
§FDA-cleared for warfarin monitoring only.
¶See [74] for list of variables and parameters.
#Beckman-Coulter, La Brea, California, manufactures the DxI800 and DXC800i.
††See [21].
‡‡See [22] and [75], for evaluation study details and panel details, respectively. See [73] for test cluster lists.
ARUP: Associated regional and university pathologists; BSL: Biosafety level; Ca++: Ionized calcium; CBC: Complete blood count; Cr: Creatinine; EUA: Emergency use authorization; Glu: Glucose; Hb: Hemoglobin; Hct: Hematocrit; Lac: Lactate; MCV: Mean corpuscular volume; MCH: Mean corpuscular hemoglobin; MCHC: Mean corpuscular hemoglobin concentration; NS: Not specified in reference no. 15; pCO2: Partial pressure of carbon dioxide; pO2: Partial pressure of oxygen; PT/INR: Prothrombin time/international normalized ratio; RBC: Red blood cell; TBil: Total bilirubin; TCO2: Total carbon dioxide content; THb: Total hemoglobin; TP: Total protein; UN: Urea nitrogen; WBC: White blood cell.
The rapid evolution of diagnostics for Ebola virus disease.
| Xpert Ebola Assay Cepheid | rRT-PCR Cartridge-based | Blood | 2 h | EUA |
| Corgenix ReEBOV & Fio Corp† | Lateral flow Ag immunoassay, Deki reader, smartphone data capture, & case tracking | Blood or plasma | 15 min | EUA |
| LIghtMix Roche cobas z480 | rRT-PCR | Blood | Over 3 h | EUA |
| QIAamp Viral Kit RealStar Filovirus: ABI Prism 7500
| rRT-PCR (Kit 1.0) | Blood, plasma | Varies with instrument | EUA |
| BioFire Defense Biothreat-E/NGDS bioMerieux§ [in 300 hospitals] | Film Array EZV Auto’d. rRT-PCR | Blood, urine (if matched to blood) | 1 h | EUA |
| MagMax Pathogen Kit, Dynal Bead Re. ABI 7500 BioRad CFX96 | CDC NP rRT-PCR | Blood, plasma, serum, urine (if matched) | NS | EUA |
| ABI 7500 | DOD EZ1 rRT-PCR | Inactivated whole | Varies with instrument | EUA |
| Nanomix [Corgenix & Tulane University] | Carbon nanotube biosensor¶ Handheld multiplex cartridge-based | Pinprick capillary blood | 10 min | No EUA# (see above) |
| Lucigen AmpliFire [Douglas Sci., UTMB, CDC] | LAMP (isothermal) 1-step, battery-operated, portable†† | RNA extract [plan 50 μL POC fingerstick capillary blood] | 40 min | No EUA# |
| Biomarkers USAMRIID/ECBC/TFS | Mass spectrometry | In development | NS | No EUA# |
| OraQuick‡‡ Orasure | CLF Ag assay [EZV, SEV, & BEV not differentiated] | In development: saliva sample | Est. 20 min | EUA# 7/31/15 [venous WB & fingerstick WB; not for screening, e.g., in airports; not for contact tracing] |
US FDA Emergency Use Authorization (EUA) status can be found at [76].
†See [77]. The WHO states, “The antigen test is rapid, easy to perform and does not require electricity-it can therefore be used at lower health care facilities or in mobile units for patients in remote settings. Where possible, results from ReEBOV antigen Rapid Test Kit should be confirmed by testing a new blood sample using an approved Ebola NAT”.
‡See [78].
§See [79].
¶See [80] and [81].
#Instrumentation and corporate/academic relationships may have changed. See “Letters of Authorization” on the FDA EUA webpage for details [82]. Contact company and investigator sources for updates.
††See [83] and [84].
‡‡See [85].
CDC: Centers for disease control and prevention; DOD: Department of defense; ECBC: Edgewood Chemical Biological Center, US Army; EUA: Emergency use authorization; EZV: Ebola zaire virus; FDA: Food and drug administration; LAMP: Loop-mediated isothermal amplification; NA: Not available; NS: Not specified in the EUA; RI: Reissued by the FDA on the given date, as explained by the FDA on the EUA webpage-only latest date listed if reissuance within 3 months; rRT-PCR: Real-time reverse transcriptase polymerase chain reaction; TFS: Thermo fisher scientific; USAMRIID: US Army medical research institute of infectious diseases; WHO: World health organization.
Figure 2.The Alere i molecular diagnostics platform and sample processing components (inset).
Figure 3.The Roche Diagnostics cobas Liat. (A) Instrument; (B) PCR-based sample processor; (C) Workflow.