The H*1 hematology analyzer. Its performance characteristics and value in the diagnosis of infectious disease

The performance characteristics and the value of data provided by the H*1 Automated Blood Cell Analyzer in the diagnosis of infectious disease are assessed. Data produced by the machine are precise over a wide range of complete blood cell counts and differential white blood cell (WBC) parameters. It is capable of accurately quantifying WBCs greater than 4000/mm³ (4 x 10⁹/L); red blood cells (RBCs), > 2.5 x 10⁶/mm³ (2.5 x 10¹²/L); and platelets greater than 1 x 10³/mm³ (1 x 10⁹/L). There is good agreement between the neutrophils and lymphocytes quantified by the standard microscopic count and the automated system; however, cells that are generally present in low incidence, namely, monocytes, basophils, and eosinophils, are less well correlated. The microscopic band cell count provides the greatest test efficiency in the diagnosis of infection. None of the unique parameters generated by the H*1 differential analyzer proved to have neither a test efficiency nor a diagnostic index greater than that of the absolute WBC count in the diagnosis of infection. The 'left shift' in the leukocyte differential count as detected by the H*1 relates poorly to the presence of band neutrophils in the specimen. It is concluded that the state-of-the-art automated leukocyte differential count can dramatically reduce work-load, but offers no advantage over the traditional differential WBC count in the diagnosis of infectious disease. Its potential value in the diagnosis of other conditions, particularly hematologic diseases, and in the sequential monitoring of infections in individual patients were not addressed by the present study.