TABLE 1.

Fever rates and attributable fractions of fever according to antigen positivity among outpatients from Angolan health facilities

Parameter and province	All samples	HRP2 positive (any level)a	HRP2 positive (ultrasensitive RDT)	HRP2 positive (conventional RDT)b	Aldolase positive (any level)a	LDH positive (any level)a
Huambo Province
No. with fever	364	69	67	56	44	32
No. with no fever	243	31	25	16	8	3
Proportion with fever (%)	60.0	69.0	72.8	77.8	84.6	91.4
Proportion of test-negative cases with fever (%)		58.2	57.7	57.6	57.7	58.0
Excess proportion with fever (%)		10.8	15.2	20.2	27.0	33.4
Excess no. of fever cases		10.8	13.9	14.5	14	11.7
Crude estimate of malaria-attributable fraction of all fever casesc		0.030	0.038	0.040	0.039	0.032
Latent class estimate (95% CI) of malaria-attributable fraction of all fever casesd		0.047 (0.004–0.097)			0.03 (0.003–0.077)	0.017 (0.001–0.047)
Uíge Province
No. with fever	433	291	282	238	210	112
No. with no fever	214	89	80	51	36	16
Proportion with fever (%)	66.9	76.6	77.9	82.4	85.4	87.5
Proportion of test-negative cases with fever (%)		53.2	53.0	54.5	55.6	61.8
Excess proportion with fever (%)		23.4	24.9	27.9	29.8	25.7
Excess no. of fever cases		88.9	90.2	80.6	73.2	32.8
Crude estimate of malaria-attributable fraction of all fever casesc		0.205	0.210	0.186	0.169	0.076
Latent class estimate (95% CI) of malaria-attributable fraction of all fever casesd		0.329 (0.244–0.405)			0.271 (0.182–0.361)	0.117 (0.026–0.200)

^aPositive for any antigen level, as assessed with an ultrasensitive, bead-based, laboratory assay.

^bHRP2 concentration above the threshold of 3,000 pg/ml for a conventional RDT (SD Bioline Pf/Pv).

^cAssessed as the ratio of excess fever cases to all fever cases.

^dAssessed using the latent class model fit to quantitative data on protein concentrations (see text).