Quality Control for Coulter Counter Models

Abstract

In this laboratory, we have been using a method of quality control for our Coulter Model S which is not related to commercial whole blood standard preparations. In the national quality control trials, it has been found consistently that participants using Coulter S produce a lower mean value for haemoglobin than with other systems and, although the difference is in the order of 0-2-0-3 g/dl, 0.5 g/dl is just within 2 SD. Although there is no definite information, it seems likely that this discrepancy is due to the use of 4C as a calibrating material by the majority of Coulter S users, but not by others. A trial is now planned which will include calibrated whole blood, a cyanmethaemoglobin preparation, and the ICSH Intemational Reference Preparation in order to try to identify the cause of the discrepancy.

West Midlands regional quality control scheme for haematology.

“…equipment. It appeared that some laboratories were Prangnell and Johnson (1976) showed that the stated using commercial reference controls as standards and value for haemoglobin for a commercial reference not checking against a cyanmethaemoglobin control differed by 0 5 g/dl from the reference standards approved by the ISCH. Platelet count results varied greatly.…”

Humidity and sterilisation by steam and formaldehyde.

“…In a recent letter to the Editor, Prangnell and Johnson (1976)1 pointed out that, using a Coulter Counter S with calibration of the haemoglobin levels against three cyanmethaemoglobin standards, the results averaged 0 5 g/dl higher than in laboratories using Coulter 4C to calibrate their machines. In the same way, Lewis (1976), in a comment on this letter, says that in the national quality control trials it has been found that participants using Coulter S produce a lower mean value for haemoglobin than when using other systems, although the difference is in the order of 0-2-0-3 g/dl; 0 5 g/dl is just within 2SD.…”