Egg Counting Procedures (Quantitative Fecal Analysis)
The most common method of determining fecal egg counts (FEC) is the modified McMaster technique which is used by Eggzamin and many of the leading diagnostic labs around the world and has been the standard for obtaining fecal egg counts in grazing animals for decades. Although there are several variations of how this is done, the basic method uses a weighed fecal sample, a known dilution in the flotation solution, and a specialized counting slide to count the eggs. The principle uses of quantitative FEC’s are to evaluate drug efficacy and potential drug-resistance.
When performing the Eggzamin modified McMaster FEC you are examining 1% of the sample, meaning each egg observed within the grid actually represents 100 eggs in the entire mixture. Since you started with four grams of feces, you must divide this number by four to report the results correctly in eggs per gram – or simply multiply the number of eggs counted by 25.
Here are a few of the labs utilizing the the modified McMaster technique:
Idexx, Auburn University, University of California, Davis, Texas A&M University at College Station, Penn Veterinary Medicine – PADLS laboratories, Texas Veterinary Medical Diagnostic Laboratory, Kansas State Veterinary Diagnostic Laboratory, University of Florida Veterinary Diagnostic Laboratories, Iowa State University College of Veterinary Medicine, North Carolina Veterinary Diagnostic Laboratory System.
