Serial PEF measurements as a diagnostic tool

To do PEF-measurements, you need a PEF-meter. PEF-meters come in different designs. This is one example.We will now demonstrate how to use the PEF-meter. Move the indicator to the lowest end of the numbered scale. Inhale deeply and blow out as forcefully as you can.

Repeat two more times…and write down the highest result from the three attempts. After several weeks the results can be plotted

into a diagram like this: In this figure, the time elapsed or days, are shown on the X-axis. The Y-axis shows the PEF measurements, given as the maximum value, shown as the green line, the minimum value, shown as the blue line, and the mean value, the red line, for each single day. The patient was AT work on the days shown in yellow and NOT at the workplace on the days indicated by the grey colour. As you can see, in this graph, there was a tendency for the PEF-values to be lower on workdays (yellow colour), compared to days out of the workplace (the grey colour). Within the workdays, you can even see a tendency of more variable PEF values.

In this case the measurements are indicative of a work-related asthma.