TABLE 7.

Agreement between 24-h and 6-h CD4 counts by method^a

CD4 stratum and laboratory	n	Median CD4 count		Agreement, TruCount			Pb	Median CD4 count		Agreement, predicate			P
		24-h	6-h	10th	50th	90th		24-h	6-h	10th	50th	90th
All strata
All labs	1,120	211	219	−39	−2	39	<0.01	209	200	−38	4	81	<0.01
A	224	269	279	−26	6	56	<0.01	289	254	−12	25	115	<0.01
B	224	173	183	−47	−8	42	<0.01	200	210	−22	20	114	<0.01
C	224	237	224	−18	1	56		190	194	−45	0	65
D	224	213	217	−42	−3	26	<0.01	179	191	−80	−12	13	<0.01
E	224	186	192	−56	−9	10	<0.01	158	177	−34	0	47
<200
All labs	560	104	108	−23	−3	15	<0.01	109	103	−26	0	33
A	80	171	173	−16	4	26	<0.05	152	144	−12	10	160	<0.01
B	112	115	119	−29	−7	18	<0.01	136	113	−19	13	74	<0.01
C	112	60	58	−13	0	14		39	49	−34	−1	28
D	128	109	115	−22	−2	10	<0.01	90	104	−30	−5	7	<0.01
E	128	104	115	−26	−6	2	<0.01	87	96	−34	−2	19
≥200
All labs	560	400	387	−59	−1	62		401	370	−57	18	103	<0.01
A	144	320	312	−35	8	66		361	305	−15	37	104	<0.01
B	112	401	401	−72	−11	67		498	443	−25	52	142	<0.01
C	112	418	389	−31	18	91	<0.01	402	368	−66	12	98
D	96	473	492	−66	−8	39		406	451	−116	−33	31	<0.01
E	96	269	279	−82	−23	26	<0.01	262	252	−34	9	91	<0.02

^aAgreement was determined by subtracting the 6-h absolute count from the 24-h absolute count (cells per microliter) obtained for the same sample by the same method. The estimated 10th, 50th, and 90th percentiles of the differences in absolute counts were determined. 

^bP value for the estimated 50th percentile, the Wilcoxon signed-rank test.