Accurate sizing is key for proper identification.
- Superimpose the ocular micrometer over the oocyst
- Place the left edge of the widest point of the oocyst on a line of the micrometer
- Count the number of units to the right edge of the oocyst
- Convert the number of units counted to micrometers (uM) using the ocular micrometer conversion factor previously determined for the microscope
- Repeat for the longest point of the oocysts (if ovoid)
2 photos of Cryptosporidium oocysts with micrometer superimposed to show width and length