Lysing reagent system for isolation, identification and/or analysis of

Abstract

A method and reagent system are disclosed for the rapid isolation, identification and/or analysis of leukocytes from a whole blood sample. The method and reagent system of this invention has application to any environment in which the study and/or analysis of the leukocyte fraction of whole blood requires their isolation in their native or near native state. One of the environments in which this invention can be used to advantage is in the performance of white cell differentiation on automated instrumentation designed for that purpose. In one of the preferred embodiments of this invention, the lytic reagent can contain a mixture of both formic and acetic acid, with the formic acid comprising the major component thereof and the acetic acid being present in only minor quantities, (if at all). This reagent system is used to selectively effect stromatolysis of red blood cells and create subtle modifications to the leukocyte population to enable their automated differentiation into five (5) sub-populations. The advantage and uniqueness of this reagent system is the surprising speed at which it is able to effect the foregoing objectives (generally less than 10 seconds at room temperature) and the ability to further differentiate the leukocyte population (notably, the granulocyte population). Following stromatolysis, a quenching agent is added to retard the reactivity of the lytic reagent system and, thus, inhibit any further dramatic changes to the leukocyte population. The treatment of the whole blood sample in the foregoing manner is further unique in that the leukocyte fraction of the sample has retained its characteristic immunochemical response.