The following is a demonstration of the scanning technique for a special stain (Iron Haematoxylin/Modified Acid Fast Stain).

Scan the entire slide using the 10x objective looking for cysts, eggs and larva and at least 300 fields using the 40x or 50x oil. The 100x oil may be used for critical examination as required.
CMLTO Recommendations for Parasitology Workloads
Experienced and competent MLT's should spend an average of 12 minutes screening a special stain before calling it negative.
For a complete copy of the Workload Guidelines for Parasitology Technologists you can contact the CMLTO