Innovative PCR without DNA extraction for African sickle cell disease diagnosis

Figures & data

Figure 1. Human Hb S/C LAMP test procedure. RT, room temperature.

Table 1. Interpretation criteria for the Hb S/C kit.

Genotype	Peaks – Tm (°C)	Level of fluorescence
HbA/HbC	46.6 +/− 1	Up 500
	52.1 +/− 1	Up 500
HbA/HbS	52.1 +/− 1	Up 500
	59.1 +/− 1	Up 500
HbS/HbC	46.6 +/− 1	Up 500
	59.1 +/− 1	Up 500
HbS/HbS	59.1 +/− 1	Up 500
HbA/HbA	52.1 +/− 1	Up 500
Positive control	46.4 +/− 1	Up 500
	52.0 +/− 1	Up 500
	58.7 +/− 1	Up 500
Negative control	No peak up the threshold	No peak up the threshold

Tm = Melting temperature.

Figure 2. Result obtained with the Human Hb S/C LAMP method. (a) Graphical presentation of a result. The HbC, HbA and HbS peak are indicated on the graph. The melting curve for the positive plasmid control (ctl+), with three peaks, is presented in bold blue. The negative control (ctl−) is presented in pink. (b) Graphical presentation of the doubtful HbAS sample, indicated in bold blue. A small HbS peak is visible but is not detected by the software due to the limited peak deepness.

Table 2. Results from the Hb S/C LAMP method and standard procedures.

Genotype^a	Blood samples		Dried blood cards		Total
	n	Number of samples correctly genotyped with HbS/C Kit	n	Number of samples correctly genotyped with HbS/C Kit	n	Number of samples correctly genotyped with HbS/C Kit
HbAA	31	31	102	102	133	133
HbAS	11	11	39	39	50	50
HbSS	5	5	7	7	12	12
HbSC	0	0	2	2	2	2
HbAC	2	2	30	30	32	32
HPFH	1	0	0	0	1	0
Minor βthal	4	0	0	0	4	0
HbAD	1	0	6	0	7	0
S/βthal	1	0	0	0	1	0
HbAE	0	0	6	0	6	0
Total	56	49	192	180	248	229

^aGenotype as obtained with reference methods.