Fig. 7
Lower limit of detection/quantitation and reproducibility (%CV = 7 %) of the urinary OspA Lyme test. a Sensitivity studies on three independent replicates: lower limit of detection (LLD) is 1.7 pg/mL. The lower limit of quantitation (LLQ) is 4.2 pg/mL for a 40 mL urine sample input volume. (Background estimate = 1071 AU, standard deviation (SD) = 323 AU. LLD = background + 2*SD, LLQ = background + 10× SD; polynomial equation y = −19.026x2 + 1160x − 248.76, R2 = 0.9971, was used to estimate the corresponding x value (1.7 pg/mL and 4.2 pg/mL, respectively)). Insert: 1 ladder; 2 Bb Lyme antigen control 1000 pg; 3 Eluate from Nanotrap particles incubated with 40 mL of volunteer urine containing no Bb Lyme antigen, negative control; 4–10 Eluate from Nanotrap particles incubated with 40 mL of volunteer urine containing decreasing concentrations of OspA, 30, 15, 7.5, 3.75, 1.9, 0.9, and 0.47 pg/mL, respectively. b Within run assay %CV is 7 %. Lyme antigen (1200 pg) was spiked in 4 urine aliquots (40 mL) and incubated with 4 mL of Nanotrap particles. Band intensity was measured with Image J. Within run %CV = 7 %. 1 Ladder; 2 OspA Lyme antigen control 200 pg, 3–6 Replicates of Nanotrap particle processed spike-in samples