Patent ID: 8158434

Claim:
A method for enumerating cellular elements within a biologic fluid sample, comprising the steps of: providing a chamber formed between a first planar member that is transparent and a second planar member, which members are separated from one another by a substantially uniform height, and which chamber has a known volume; introducing the biologic fluid sample into the chamber in an amount such that the sample extends between the first and second members for substantially the entire extent of the chamber, which fluid sample has first cellular elements having a first thickness and second cellular elements having a second thickness; selecting the chamber height relative to the first and second thicknesses such that the first and second cellular elements non-uniformly distribute within the sample upon introduction into the chamber; examining substantially all of the sample within the chamber in an unlysed state and enumerating all of at least one of the first and second cellular elements non-uniformly distributed within the chamber; and determining a number per unit volume of sample of the at least one of the cellular elements.