Table 1

 Dark ground microscopy

Obtaining the specimen
• Cleanse lesion with saline using gauze swab
• Dry and abrade with dry gauze swab; or abrade with scalpel for intact papule or healing ulcer if necessary
• Squeeze clear serum—do not dilute with saline
• Collect oozing serum with edge of coverslip
• Put coverslip onto slide
• Press between filter paper evenly
Dark field microscope
• Use a dark field condenser
• Place 1 drop of oil on bottom of slide where the specimen is
• Put slide on the stage ensuring oil contact between condenser and slide
Objective ×10
• Focus
• Close field diaphragm and centre the circular light beam with centring screws
• Open field diaphragm
Objective ×40
• Search
Objective ×100
• Place oil on top of the coverslip before using objective.
• Adjust the iris diaphragm in the objective for “darkness” of field
• Detail identification of spirochaetes looking for characteristic morphology and motility