Recommendation for collection of skin puncture blood from children, with special reference to production of reference values.

Reliable reference values need to be collected under standardized conditions. In order to enable comparison of values observed on patients with reference values, it is also desirable to use the same standardized conditions on patients. The present recommendation was produced as a joint effort of representatives of the clinical chemists and paediatricians of Scandinavia and describes the following details. Preparation of the child before specimen collection (food intake, time of day, physical activity, posture, environment), preparation of skin puncture site (warming, disinfection, ointment), instruments for blood collection (lancet, blood collection vessel), site of puncture (plantar surface of foot, finger, ear lobe), collection of emerging blood and handling and storage of the specimen.

Gas-liquid chromatographic determination of mexiletine in human serum with nitrogen sensitive detection.

A simple and rapid method for the quantitative determination of mexiletine, using gas-liquid chromatography with nitrogen sensitive detection, is described. Only one extraction step is needed, the recovery is between 92-96% and the precision varies between 2.0--5.5%. The lower limit of detection reached 0.5 micro mol/1. During routine handling the method was easy, quick and cheap.