Determining % parasitemia in malaria smears

[colleenbennett]

We have had recent positive malaria smears and needed to give a % parasitemia to the physicians. The literature states to determine the average number of RBCs/ oil immersion field. Then do the following calculation.

Total number of parasites in 100 fields

------------------------------------- = % parasitemia

Number of RBCs/field x 100 fields

Can this be accomplished by doing a count similar to a retic count using the Miller Occular?

Just wondering how everyone else determined % parasitemia.

[SMILLER]

Seems like a good idea! If we ever get a request like that, that's how I am going to do it!

[Bill]

What is the value of this? Is there literature that states that the higher the %, the sicker the patient or similar?

[Steven Jeff]

In the UK we would only estimate the parsitemia % on falciparium films. Personally I think 100 fields is a lot to count, a field on the microscope I use would have 250 to 300 red cells. This equates to 25,000 to 30,000 red cells. Provided the film you are looking at has a good uniform spread of cells then I doubt that there is any more accuracy in counting 100 fields.

Bill, I believe % parasitemia is required to monitor treatment

Steve

:)