MethComp (version 1.30.0)

hba1c: Measurements of HbA1c from Steno Diabetes Center

Description

Three analysers (machines) for determination of HbA1c (glycosylated haemoglobin) were tested on samples from 38 individuals. Each had drawn a venous and capillary blood sample. These were analysed on five different days.

Format

A data frame with 835 observations on the following 6 variables.

dev

Type of machine used. A factor with levels BR.V2, BR.VC and Tosoh.

type

Type of blood analysed (capillary or venous). A factor with levels Cap Ven

item

Person-id. A numeric vector

d.samp

Day of sampling.

d.ana

Day of laboratory analysis.

y

The measured value of HbA1c.

Details

In the terminology of method comparison studies, methods is the cross-classification of dev and type, and replicate is d.ana. It may be of interest to look at the effect of time between d.ana and d.samp, i.e. the time between sampling and analysis.

References

These data were analysed as example in: Carstensen: Comparing and predicting between several methods of measurement, Biostatistics 5, pp. 399--413, 2004.

Examples

data(hba1c)
str(hba1c)
hb1  <- with( hba1c,
              Meth( meth = interaction(dev,type),
                    item = item,
                    repl = d.ana-d.samp,
                       y = y, print=TRUE ) )