Table 2.

Probability of sera used in the potency assay to retain transmission-blocking (TB) or enhancing activities upon dilution

TB categories (% reduction)*	Probability of sera to retain TB activity†
	90–100‡	50–89‡	0–49‡	< 0‡
90–100	0.06	0.02	0.00	0.00
50–89	0.43	0.40	0.05	0.06
0–49	0.24	0.36	0.26	0.39
< 0 (enhancing)	0.27	0.22	0.69	0.55

^*Categories of transmission-blocking activity to classify the percentage reduction of infected mosquitoes and oocyst count.

^†Analysis of the probablity of 37 sera at 2-fold dilution (1:2 to 1:64) to retain the ability of blocking at any of the TB categories.

^‡Classification of percentage of transmission–blocking activity in 37 undiluted sera.