Table 2.

Comparison of total body water (TBW) measured by ²H dilution and predicted from bioelectrical impedance analysis by using the published equations, in the eighty-eight measurements performed in thirty-four HIV-infected African outpatients^†

Published equation	Correlation coefficient between TBW measured and predicted*	Bias (kg)‡		P value	95 % limits of agreement (kg)§	Pure error (kg)∥	Correlation between mean and difference of the two methods	P value
		Mean	sd
A	0·94	−1·70	2·38	<0·0001	−6·36, + 2·96	2·92	0·35	0·0006
B	0·93	−0·97	2·71	0·0011	−6·28, + 4·34	2·86	0·11	0·31
C	0·91	−3·06	3·01	<0·0001	−8·96, + 2·84	4·28	0·29	0·26
D	0·95	−4·34	2·21	<0·0001	−8·67, 0	4·87	0·092	0·52
E	0·94	+1·32	2·47	<0·0001	−3·52, + 6·16	2·79	0·10	0·35
F	0·94	−1·69	2·47	<0·0001	−6·53, + 3·15	2·98	0·22	0·050
G	0·94	−1·51	2·56	<0·0001	−5·53, + 3·05	2·96	-0·017	0·89
H	0·91	−2·34	3·59	<0·0001	−9·38, + 4·70	4·27	-0·33	0·0052
I	0·94	+0·11	2·34	0·67	−4·48, + 4·70	2·33	0·12	0·24
J	0·91	−1·85	3·16	< 0·0001	−8·04, + 4·34	3·65	−0·032	0·79
K	0·56	−3·21	10·39	0·0057	−23·57, + 17·15	10·81	0·59	0·021
L	0·95	−4·05	2·28	< 0·0001	−8·52, + 0·42	4·64	0·10	0·34
M	0·93	−0·36	2·75	0·23	−5·75, + 5·03	2·76	0·055	0·62
N	0·94	+1·25	2·44	< 0·0001	−3·53, + 6·05	2·73	0·035	0·75
O	0·90	+1·34	3·22	< 0·0001	−4·97, + 7·65	3·47	0·10	0·39

^*P<0·05 for all.

^†For details of subjects and procedures, see Subjects and Methods. For details of the published equations, see Table 1.

^‡Measured - predicted value (a negative value of the bias reflects an overestimation by the prediction equation).

^§95 % CI of the individual differences.

^∥Pure error = √Σ(measured - predicted)²/n, where n is the number of measurements. The smaller the pure error the greater the accuracy.