Highly Sensitive Loop-Mediated Isothermal Amplification for the Detection of Leptospira

Table 2

Detection limit in normal human plasma spiked with genomic DNA.

Starting material (cp/mL)	2000 (1111)^a	1000 (555)	500 (278)	200 (111)	0
200 μL for extraction (cp)	400	200	100	40	0
Elute in 20 μL (cp/μL)^b	20	10	5	2	0
Add 5 μL in LAMP (cp)	100	50	25	10	0
qPCR quantification^c (cp)	72 (65~84)	33 (28~40)	12 (8~20)	ND	ND^d
LAMP result	pos.	pos.	neg.	neg.	neg.

Estimated cp per mL of whole blood, as plasma constitutes 55% of the total blood volume.
^bAssuming 100% recovery for the extraction steps.
^cCopy numbers are based on standard curves obtained from diluted pL32 plasmid. They are the average of three independent experiments (range of detection).
^dND: not detected.