The specimen was labeled "Mast" and had a number so he called the American Museum to find out if they had any missing specimens.
Of the 321 (72%) of 444 eligible households with at least two thirds of individuals with complete data, there were 914 members, 91 (10%) of whom were missing specimen data.
This subgroup was however similar to the group included except for histological subtype: leiomyosarcomas were overrepresented in missing specimen.
In order to correctly calculate the incremental yields, we added the observed proportions of positive smears or cultures to the expected proportion for the missing specimens, using a method described by Rieder et al. (Appendix)[ 19].
"It has long been our intent to treat these people with dignity and respect," said Gerald S. Levey, vice chancellor of the U.C.L.A. School of Medicine, who insisted there was no evidence that the missing specimens were used for any purpose other than medical research.
However, we were able to estimate the proportion of positives for the missing specimens using established formulas [ 19].
The rate adjusted for missing specimens and contaminated cultures was 32.6 (95% CI, 28.1 37.7) and the rate adjusted, in addition, for access to care was 36.4 per 100 000 PYO (Table 2).
We conducted a brief survey of hospital personnel to understand the major reasons for missed specimen collection.
We missed specimen collections because of complications during delivery, premature birth and/or small size of the infant resulting in a small quantity of available cord blood, and limited staffing.
Infants with missed specimen collection or insufficient blood volumes, on average, had shorter gestations and/or lower birth weight and were more likely to have been firstborn or born to younger mothers.
All missed specimens had a body length < 5 mm (Additional file 3: Figure S5).
