Patent ID: 7169357

Claim:
An automatic chemical analyzer capable of determining plural components of samples by using independent reagents for respective components of said samples, comprising a sampling mechanism having a sampling probe that dispenses the samples to reaction vessels and a mechanism for pipetting plural kinds of reagents with a same reagent pipetting probe from a reagent supply to the reaction vessels, said reaction vessels holding a reaction solution of said samples and said reagents that is analyzed, and a means for washing the reagent pipetting probe, and in order to prevent occurrence of errors of determination due to cross-contamination occurring among the reagents, the analyzer is provided with a control unit that functions to set determination conditions for judging the presence or absence of the cross-contamination occurring among the reagents and to make automatic judgment of the combination of items involving the cross-contamination, wherein in order to prevent the occurrence of errors of determination due to generation of new contamination by variation of the state of the washing means, the control unit makes judgment on the presence or absence of the cross-contamination for combinations of the reagents by testing a standard sample, memorizes the judgment result in relation to the reagent combinations, compares the judgment result with the judgment result of previously made judgments for the same reagent combinations; and when these results differ more than a predetermined amount, judges that the state of the washing means has changed, and indicates it to the user.