TK 210 ELISA standard curve and assay linearity.

(A) A standard curve for TK 210 ELISA with calibrators (0–18 ng/mL) using 4-PL (non-linear regression program) in Graph pad prism. The limit of detection was 0.12 ng/mL. The error bars indicate the mean and standard deviation (SD) of 10 different experiments performed in duplicate. (B) The percentage change in calibrators from the precision assays. The error bars indicate the mean and standard deviation (SD) value of the calibrator. (C) The OD values of serially diluted serum samples measured by AroCell TK 210 ELISA. (D) The correlation between expected and observed TK1 protein levels in serially diluted samples.