Table 1.

Sensitivity analysis for a single copy gene. The number of trypanosomes per reaction at which the microsatellite marker PLC was reproducibly detected by PCR amplification. 1 disc or 5 discs indicates the number of washed FTA discs used as the initial template. + indicates reproducible successful amplification and detection of both alleles, +* indicates the concentrations at which allele dropout was observed, - indicates no product observed, ND indicates not determined. Effective sensitivity is the calculated number of trypanosomes present in the individual PCR. Absolute sensitivity is the initial concentration of trypanosomes per mL of blood spotted onto the FTA card. There are two different values of effective sensitivity at the same absolute sensitivity value, due to the use of 1 or 5 FTA discs, or 1 μL (1 disc) or 0.4 μL (5 discs) or 2 μL (pooled) of MDA product, as template in the PCR.

Effective sensitivity	Absolute sensitivity	Single round PCR	Nested PCR	Absolute sensitivity	MDA and nested PCR
					1 disc	5 discs	pooled
500	1 × 105	+	+	ND	ND	ND	ND
100	1 × 105	+	+	ND	ND	ND	ND
50	1 × 104	+	+	ND	ND	ND	ND
10	1 × 104	+	+	ND	ND	ND	ND
5	1 × 103	-	+	1 × 105	+	+	+
1	1 × 103	-	+	1 × 105	+	+*	+
0.5	1 × 102	-	-	1 × 104	+	+*	+
0.1	1 × 102	-	-	1 × 104	+	+*	+
0.05	1 × 101	-	-	1 × 103	+*	+*	+
0.01	1 × 101	-	-	1 × 103	-	-	-
0	0	-	-	0	-	-	-