The CD4 depletion model estimates diagnosis delays by approximating infection date from CD4 T-cell count at diagnosis, and back-calculation can compute the proportion of undiagnosed PLWHA. The model assumes the immigration of PLWHA to the U.S. is negligible and counts as a transmission event, which may be impractical outside high prevalence states. Duration of U.S. residency among foreign-born PLWHA and diagnosis delays were compared. The impact on estimates of undiagnosed PLWHA was tested through simulation with different proportions of foreign-born people assumed to have acquired HIV abroad. In 67% of foreign-born people, the mean (SD) years of delay (9.9 (6.3)) exceeded the duration of U.S. residency (2.0 (1.9)). Additionally, inaccuracies in the estimates for proportions of undiagnosed PLWHA were pronounced when foreign-born people who acquired HIV abroad comprised 30% of diagnoses. The CD4 model inadvertently misclassified some diagnoses as in-state transmission events. Consequently, simulated results demonstrated inaccuracies and unstable calculations.

CD4 耗竭模型通过诊断时的 CD4 T 细胞计数估算感染日期来估计诊断延迟，并且反算可以计算未诊断的 PLWHA 的比例。该模型假设 PLWHA 移民到美国的数量可以忽略不计，并被视为传播事件，这在高流行州之外可能不切实际。比较了外国出生的感染者在美国居住的时间和诊断延迟。通过对假定在国外感染艾滋病毒的外国出生者的不同比例进行模拟，测试了对未确诊感染者艾滋病毒感染者估计的影响。67% 的外国出生者的平均 (SD) 延误年数 (9.9 (6.3)) 超过了美国居住时间 (2.0 (1.9))。此外，当在国外感染艾滋病毒的外国出生者占诊断人数的 30% 时，对未确诊感染者比例的估计也很不准确。CD4 模型无意中将一些诊断错误分类为州内传播事件。因此，模拟结果表明计算不准确且不稳定。