Table 1. Example calculations.

CD4 count cells/mm 3	Estimated incidence rate of HIV- related symptoms per person-year	Estimated standard error of HIV- related symptoms	Example calculation for point estimate		Example calculation for confidence interval	Example calculation for high estimate
			Number of observed HIV diagnoses with HIV-related symptoms in a year	Point estimate for the estimated number of person years lived with undiagnosed HIV in 2011 in stratum	95% confidence interval for the estimated number of person years lived with undiagnosed HIV in 2011 in stratum	Number of observed HIV diagnoses in a year	High estimate for the estimated number of person years lived with undiagnosed HIV in 2011 in stratum
0–19	4.030	0.582	5	1	0–3	9	2
20–49	1.442	0.168	14	10	5–16	19	13
50–99	0.872	0.081	14	16	8–26	25	29
100–149	0.440	0.044	7	16	5–30	22	50
150–199	0.216	0.022	13	60	29–100	31	144
200–249	0.090	0.010	3	33 a	0–80 a	34	378 a
250–299	0.076	0.007	3	39 a	0–94 a	41	539 a
300–349	0.048	0.005	4	83 a	18–176 a	57	1188 a
Total (CD4 counts 0–200 cells/mm 3)	-	-	53	103	51–165	106	238
Total (CD4 counts 0–350 cells/mm 3)	-	-	63	258 a	159–415 a	238	2343 a

Estimates for the number of person-years lived with undiagnosed HIV among MSM in the Netherlands in 2011, rounded to the nearest integer (not adjusted to take into account for missing CD4 counts or for reporting delay or under-reporting).

Note: Incidence rate and standard error of HIV-related symptoms obtained using data from the CASCADE cohort collaboration[16,17] (rate is two-fold the incidence of AIDS).

^aThese estimates should be interpreted with more caution due to the rates of HIV-related symptoms being much lower in the higher CD4 count ranges.