Use of the Hemacytometer for the Determination of Cell Numbers

Counting cells by the use of a hemacytometer is a convenient and practical method of determining cell numbers in the case that the Coulter counter is out-of-order temporarily. (It is not that bad.) The hemacytometer consists of two chambers, each of which is divided into nine 1.0 mm squares. A cover glass is supported 0.1 mm over these squares so that the total volume over each square is 1.0 mm x 0.1 mm or 0.1 mm3, or 10-4 cm3. Since 1 cm3 is approximately equivalent to 1 ml, the cell concentration per ml will be the average count per square x 104. Hemacytometer counts are subject to the following sources of error: 1. Unequal cell distribution in the sample 2. Improper filling of chambers (too much or too little) 3. Failure to adopt a convention for counting cells in contact with the boundaries lines or with each other (be consistent) 4. Statistical erro