[The "incorrect" laboratory result. II: Common misinterpretations of laboratory results]

In the second part of our review the most frequent misinterpretations of laboratory results in the daily clinical practise are discussed. Special attention has been given to frequent misinterpretations in the analysis of electrolytes, enzymes and hormones in plasma/serum (pseudohyperkalemia, macroenzymes, macroprolactinemia). Misinterpretations of the testing of blood gases, serum glucose, lipid concentrations, and calcium are described in greater detail. In addition, potential errors in the urinanalysis and the importance of adequate sampling of blood specimens for coagulation testing are described. The hematological results can be misinterpreted in the presence of EDTA-induced pseudothrombocytenia and of irregular immunoglobulines. Immunological methods themselves can lead to misinterpretations of the laboratory result, e. g. caused by the high dose hook effect and interferences in the presence of rheumatoid factor or HAMA. Finally clinical relevant errors in the therapeutic drug monitoring are discussed which are associated with the limited specificity of the antibodies in the commonly used immunological tests.