Development and clinical performance of high throughput loop-mediated isothermal amplification for detection of malaria.
BACKGROUND
Accurate and efficient detection of sub-microscopic malaria infections is crucial for enabling rapid treatment and interruption of transmission. Commercially available malaria LAMP kits have excellent diagnostic performance, though throughput is limited by the need to prepare samples individually. Here, we evaluate the clinical performance of a newly developed high throughput (HTP) sample processing system for use in conjunction with the Eiken malaria LAMP kit.


METHODS
The HTP system utilised dried blood spots (DBS) and liquid whole blood (WB), with parallel sample processing of 94 samples per run. The system was evaluated using 699 samples of known infection status pre-determined by gold standard nested PCR.


RESULTS
The sensitivity and specificity of WB-HTP-LAMP was 98.6% (95% CI, 95.7-100), and 99.7% (95% CI, 99.2-100); sensitivity of DBS-HTP-LAMP was 97.1% (95% CI, 93.1-100), and specificity 100% against PCR. At parasite densities greater or equal to 2 parasites/μL, WB and DBS HTP-LAMP showed 100% sensitivity and specificity against PCR. At densities less than 2 p/μL, WB-HTP-LAMP sensitivity was 88.9% (95% CI, 77.1-100) and specificity was 99.7% (95% CI, 99.2-100); sensitivity and specificity of DBS-HTP-LAMP was 77.8% (95% CI, 54.3-99.5) and 100% respectively.


CONCLUSIONS
The HTP-LAMP system is a highly sensitive diagnostic test, with the potential to allow large scale population screening in malaria elimination campaigns.
Department of Clinical Parasitology, Hospital for Tropical Diseases, University College London Hospitals NHS Foundation Trust, Mortimer Market, London, United Kingdom.
Rushini S
RS
Perera
FIND CH-1202 Geneva, Switzerland.
Xavier C
XC
Ding
42 Technology Ltd., Cambridgeshire, United Kingdom.
Frank
F
Tully
42 Technology Ltd., Cambridgeshire, United Kingdom.
James
J
Oliver
Porvair Sciences Ltd, Norfolk, United Kingdom.
Nigel
N
Bright
Global Good Fund, Intellectual Ventures Laboratory, Bellevue, Washington, United States of America.
David
D
Bell
Department of Clinical Parasitology, Hospital for Tropical Diseases, University College London Hospitals NHS Foundation Trust, Mortimer Market, London, United Kingdom.|London School of Hygiene and Tropical Medicine, Keppel Street, London, United Kingdom.|Department of Clinical Parasitology, Health Services Laboratories LLP, Hospital for Tropical Diseases, Mortimer Market, London, United Kingdom.
Peter L
PL
Chiodini
FIND CH-1202 Geneva, Switzerland.
Iveth J
IJ
Gonzalez
Department of Clinical Parasitology, Health Services Laboratories LLP, Hospital for Tropical Diseases, Mortimer Market, London, United Kingdom.
Spencer D
SD
Polley
D059788:Dried Blood Spot Testing; D057166:High-Throughput Screening Assays; D006801:Humans; D008288:Malaria / Q000175:diagnosis* / Q000469:parasitology*; D021141:Nucleic Acid Amplification Techniques; D010961:Plasmodium / Q000235:genetics*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity