We have previously used the proportion of specimens positive for influenza as proxy for influenza virus activity.
This assumes that the proportion of specimens that test positive for recent infection is the same for persons with available specimens and for those whose specimens were missing.
The proportion of specimens positive for Shigella spp. was also substantially lower than most other estimates in the region, which ranged from 10 16% [5], [12], [17], [18], [19].
During June 1-June 14, HAPS data on the proportion of specimens positive for pH1N1 were not available because HAPS was not performing the pH1N1 rRT-PCR assay.
Among all specimens with repeatedly reactive EIAs, we evaluated the proportion of specimens that were Western blot-negative, indeterminate, or positive, and the positive predictive value of the EIA test, by pregnancy status.
Probabilistic sensitivity analyses with 10,000 repetitions were conducted to evaluate the false-positive rate among pregnant women assuming that the proportion of specimens from persons of unknown pregnancy status to be categorized as pregnant was binomially distributed [15].
In order to calibrate the sensitivity, short-term specificity and long-term specificity, "a plot of the proportion of specimens positive in the assay versus time since seroconversion" is generated (also later referred to as "the curve").
The proportion of specimens containing acid fast bacilli (from sputum, gastric washings, bronchoalveolar lavage or fine needle aspirate of a lymph node) was comparable in the MDR-TB and control groups (p = 0.11 1.0) (Table 2).
Nevertheless, when the proportion of specimens found to be infected on follow-up were removed, pregnant women were not more likely to have false-positive HIV EIA test results than others testing for HIV, as previously thought.
