Fig 1.
Schematic of sample processing and lateral flow assay.
(a) Combination of serum sample with high-pH buffer. (b) Heating of serum solution. (c) Addition of acidic buffer to lower pH. (d) Application of prepared serum solution to LFA. (e) Application of running buffer. (f) Addition of FITC conjugates to nitrocellulose membrane.
Fig 2.
(a) Mean T/C ratio versus folate concentration for 24 human serum samples. Error bars shown are standard deviation, n = 3. Dotted line shows four-parameter logistic curve fit. (b,c) Images of fluorescent signal from test strip for low and high folate concentration serum, respectively.
Fig 3.
Receiver operating characteristics curves for two different cutoff concentrations.
(a) Cutoff at 13.4 nmol/L folate concentration. (b) Cutoff at 10 nmol/L folate concentration.
Fig 4.
Serum results without heat denaturation and without washing and secondary addition of FITC conjugates.
(a) Mean T/C ratio versus folate concentration for 6 serum samples tested without heating. Error bars shown are standard deviation, n = 3. (b) Mean T/C ratio versus folate concentration for 6 serum samples tested in a traditional lateral flow assay format. Error bars shown are standard deviation, n = 3.