title: A lab-on-chip for malaria diagnosis and surveillance.
abstract: BACKGROUND
  Access to timely and accurate diagnostic tests has a significant impact in the management of diseases of global concern such as malaria. While molecular diagnostics satisfy this need effectively in developed countries, barriers in technology, reagent storage, cost and expertise have hampered the introduction of these methods in developing countries. In this study a simple, lab-on-chip PCR diagnostic was created for malaria that overcomes these challenges.
  
  
  METHODS
  The platform consists of a disposable plastic chip and a low-cost, portable, real-time PCR machine. The chip contains a desiccated hydrogel with reagents needed for Plasmodium specific PCR. Chips can be stored at room temperature and used on demand by rehydrating the gel with unprocessed blood, avoiding the need for sample preparation. These chips were run on a custom-built instrument containing a Peltier element for thermal cycling and a laser/camera setup for amplicon detection.
  
  
  RESULTS
  This diagnostic was capable of detecting all Plasmodium species with a limit of detection for Plasmodium falciparum of 2 parasites/μL of blood. This exceeds the sensitivity of microscopy, the current standard for diagnosis in the field, by ten to fifty-fold. In a blind panel of 188 patient samples from a hyper-endemic region of malaria transmission in Uganda, the diagnostic had high sensitivity (97.4%) and specificity (93.8%) versus conventional real-time PCR. The test also distinguished the two most prevalent malaria species in mixed infections, P. falciparum and Plasmodium vivax. A second blind panel of 38 patient samples was tested on a streamlined instrument with LED-based excitation, achieving a sensitivity of 96.7% and a specificity of 100%.
  
  
  CONCLUSIONS
  These results describe the development of a lab-on-chip PCR diagnostic from initial concept to ready-for-manufacture design. This platform will be useful in front-line malaria diagnosis, elimination programmes, and clinical trials. Furthermore, test chips can be adapted to detect other pathogens for a differential diagnosis in the field. The flexibility, reliability, and robustness of this technology hold much promise for its use as a novel molecular diagnostic platform in developing countries.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Taylor
authors.forename: Anita
authors.initials: A
authors.lastname: Howell
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Martin
authors.forename: Dammika P
authors.initials: DP
authors.lastname: Manage
authors.forename: Walter
authors.initials: W
authors.lastname: Gordy
authors.forename: Stephanie D
authors.initials: SD
authors.lastname: Campbell
authors.forename: Samantha
authors.initials: S
authors.lastname: Lam
authors.forename: Albert
authors.initials: A
authors.lastname: Jin
authors.forename: Spencer D
authors.initials: SD
authors.lastname: Polley
authors.forename: Roshini A
authors.initials: RA
authors.lastname: Samuel
authors.forename: Alexey
authors.initials: A
authors.lastname: Atrazhev
authors.forename: Alex J
authors.initials: AJ
authors.lastname: Stickel
authors.forename: Josephine
authors.initials: J
authors.lastname: Birungi
authors.forename: Anthony K
authors.initials: AK
authors.lastname: Mbonye
authors.forename: Linda M
authors.initials: LM
authors.lastname: Pilarski
authors.forename: Jason P
authors.initials: JP
authors.lastname: Acker
authors.affiliation: School of Public Health, University of Alberta, WMC 2B4,59, 8440 - 112th Street, Edmonton, AB, Canada. yanow@ualberta.ca.
authors.forename: Stephanie K
authors.initials: SK
authors.lastname: Yanow
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D056656:Lab-On-A-Chip Devices; D008288:Malaria / Q000175:diagnosis* / Q000469:parasitology; D025202:Molecular Diagnostic Techniques / Q000295:instrumentation* / Q000379:methods*; D010961:Plasmodium / Q000145:classification / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction / Q000295:instrumentation* / Q000379:methods*; D011247:Pregnancy; D012680:Sensitivity and Specificity; D014454:Uganda; D055815:Young Adult