The referent method for serologic diagnosis of leptospirosis is the microscopic agglutination test (MAT).
Disparity in results between clinical and reference laboratories could also contribute to this trend; use of the E test (AB Diodisk, Solna, Sweden) by clinical laboratories might vary from the referent method (broth microdilution) by one half or one dilution (18 ).
In the every-third-day referent sampling method, day-of-week variable was included in the regression model.
We tested the effects of time (15min, 6 and 18h) on IGF-IR/IR and Akt (Ser 473) phosphorylation after stimulation with 10nM of each ligand (21), and compared by deriving phosphorylation ratios with insulin as referent (details in Methods).
The case-crossover design (Maclure 1991) requires a choice of referent strategy or a method for choosing control time periods (referent windows).
Since the development of the case-crossover design, the time-stratified approach has been recognized as being the least-biased method among referent (control) selection strategies (Basu et al. 2005; Janes et al. 2005).
As mentioned earlier, we evaluated each model by comparing model-generated public-sector prevalence rates for each short-acting method with corresponding DHS values using MAE and by examining the proportion of countries where the model-estimated prevalence rate was within 1, 2, or 5 percentage points of the DHS referent value for the method.
Bi-directional time-stratified methods commonly select referent days to include non-case days on the same day of week, month, and year as the event, which can control for seasonal trends and day-of-week [ 52, 53].
The aim of this work was to study how machine milking (MM) carried out in appropriate conditions affects teat wall thickness and canal length and their return after milking to premilking conditions compared with other milk removal methods considered biological referents: kid suckling (KS), catheter removal (CATH), and hand milking (HM).
Janes et al. suggest using the time stratified approach as a standard method in selecting referent periods, as it ensures unbiased estimation and avoids bias resulting from time trends in the exposure [ 25].
