Surgery and Healing in the Developing World - Dartmouth-Hitchcock

8
66 Surgery and Healing in the Developing World
Blood
Widal Test for Salmonella Typhi and Paratyphi (A, B and C)
The Widal test is used to detect antibodies in the blood to the organism. This
test can be performed with the aid of a manufacturers kit that contains both the
necessary reagents and instruction on use. Serum or plasma can generally be used
for detection. Consult the kt for specific instructions.
VDRL (Veneral Disease Research Laboratories)
VDRL is used to detect Treponema pallidum in patents suspected of having syphilis.
This test can be done with the aid of a manufacturer’s kit. Consult kit for details on
procedure.
Urine Analysis
Urine can be collected in glass bottles. If a centrifuge is available pour urine into
a glass test tube, and spin at 1500 rpm for 10 min. Pour off the liquid leaving the
sediment behind. Remove sediment and place a small amount on a glass slid and
cover with a slip taking care not to introduce bubbles. If no centrifuge is available
allow urine to sediment for 3-4 hours then carefully remove all but the sediment and
continue as above. Examine under microscope as for Leishman stain. Things to note
include bacteria, casts, crystals, cells and yeast.
Parasites
Blood
The Field Stain
Field stain is commonly used to detect the presence of malaria parasites in the
blood of patients exhibiting symptoms of the malaria. Although Leishman stain can
also be used to detect the parasites, Field stain is easy to use and gives the best results.
This stain will also detect trypanosomiasis and filaria. To detect parasite obtain
anti-coagulated patient blood sample.
Field Stain Procedure
1. Make a thin and thick smear of patient’s blood. (Note: Both smears must
be stained and examined to ensure correct diagnosis).
2. Fix smear with heat for 3 sec.
3. Cover smear with solution A for 5 sec.
4. Wash smear with running water for 5 sec, or until water runs clear.
5. Cover smear with solution B for 3 sec.
6. Repeat wash.
7. Allow smear to air dry and view under microscope.
Microscopic Observation of Field Stain
Examine the smear under the microscope as previously described. Be sure to
thoroughly examine the smear for a full 5 min before determining that it is negative.
The parasite form will vary depending on the stage of the cycle and the type of
malaria. A color atlas of malaria parasites should be included in the suitcase to enable
comparison. The degree of infection can be determined by calculating the number
of infected red blood cells. The more parasites present the more severe the disease.