An assessment of the Ortho ELT-8

The Ortho ELT-8 is an automated blood counter which appears to be safe, precise and free from carry-over. Red and white cell results generally agree with those on the Coulter Counter, Model S, though discrepancies were noted with the WBC and PCV. Reference methods showed the Model S WBC results tended to be inaccurate on the discrepant samples though neither instrument was predominantly responsible for the PCV discrepancies. The ELT-8 platelet count tended to be higher than with the Thrombocounter/Thrombofuge system. When packed cells were diluted in autologous plasma serious variations in the red cell indices (MCV, MCH & MCHC) were first found due to incorrect voltage-frequency converter setting. Even after this setting had been corrected some variations in the MCH and MCHC were still apparent. In the UK National External Quality Assessment Scheme the ELT-8 results on animal bloods did not agree with those produced by Model S users; this discrepancy probably being due to differences between the light-scattering and aperture-impedance technology.