Hematology & Hemostasis

TITLE:

Determination of Total Red Blood Cell Count (manual method)

PRINCIPLE:

To facilitate the counting of red blood cells a 4.0ml of diluting fluid was mixed well with 20ul of whole blood in a 10 x 75mm test tube. The mixture was added to the Neubauer Haemocytometer and allowed to settle. The red blood cells were viewed at 10 x objective and then 40 x dry objective which aided in counting of the cells on the 5 smaller squares. The total RBC count can then deduced by use of a formula.

METHOD:

Same as laboratory handout.

CLINICAL SIGNIFICANCE:

The physician may order a red blood cell count as part of a complete blood count as a routine check or if he/she sees signs and symptoms suggesting you may have a condition that affects your red blood cells. Also, if a patient shows signs of breathlessness, fatigue or pale skin a RBC can be ordered as the physician may want to check on your hemoglobin levels. An individual that has a lower than normal RBC range will also have a relatively low hemoglobin concentration and therefore a lower level of oxygen going to the tissues. Normal ranges are as follows females 3.5-4.5 x 10^12/L, males 4.0-5.5 x 10^12/L and babies 5.0-6.5 x 10^12/Higher than normal ranges in males, females and babies can indicate Polycythemia and a lower than normal range may be an indication of anemia.

SOURCES OF ERROR:

- Overflow of liquid in the moot and failure to remove this excess liquid

- Failure to allow cells to settle prior to counting

- Inadequate or improper mixing of the test tube after dilution

- Failure to focus microscope up and down during counting

- Failure to make a 1:101 dilution to ensure an accurate count when there are severe cases of anemia and total RBC is very low

- When total red cell count is very high it may be difficult to obtain an accurate count.

- Strenuous physical activity tends to increase the red cell count

- Failure to remove...