Surgery and Healing in the Developing World - Dartmouth-Hitchcock

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62 Surgery and Healing in the Developing World
and donor if a transfusion is necessary immediately. Once a match is made, obtain
the necessary blood and transfuse the patient in a timely fashion. The use of blood
typing agglutination kits purchased and carried in the suitcase will allow for rapid
typing. Follow instructions on the kit. Agglutination (clumping) of sample indicates
blood type. If matched, isolate the blood using 16G or 18G sterile needles and
prepackaged blood transfusion bags containing citrate to prevent coagulation.
Hematology and Serum Chemistry
A few tests have been chosen which are deemed essential to basic patient care.
Basic Blood Tests
Differential and TLC
These blood tests can be performed easily. After obtaining the anticoagulated
blood specimen (mix 4.5 ml blood with 0.5 ml sodium citrate) from the patient
blood films on a glass slide are made. This can be done by first putting a small drop
of blood on one end of the slide and then, using another slide, smear the drop with
the edge.
Leishman Stain
This staining procedure is widely used for distinguishing between different types
of normal blood cells. Each cell stains in a different pattern when viewed under the
microscope and will allow for easy identification. Note: The stains described will
stain hands and clothing as well as bacteria. Do not wear good clothes in the laboratory,
wear gloves when staining, and keep in mind that all stains are assumed to be
toxic unless otherwise stated.
Leishman Stain Procedure
1. Prepare blood film.
2. Allow the sample to air dry for a few minutes.
3. Once dry, cover film with 10 drops of Leishman stain using an eyedropper
and allow to sit for 30 sec.
4. Add 20 drops of water and let sit for 15 min.
5. Pick up slide with forceps and rinse in fast running tap water for 1 sec.
6. Allow to dry.
7. Examine under microscope using an oil immersion lens.
Microscopic Observation of a Leishman Stain
Differential: A good approach to observing any smear is to examine it under low
power (10X) in a bright field for orientation. After focusing, work up to 40X and
finally 100X. Be sure that the smear is not upside down, or focusing will not be
possible. When doing a differential, count 100 cells in the following way to obtain
the percentage of white cells (Fig. 3).
TLC: A TLC can be done by staining with Leishman’s on a hemocytometer as
opposed to a simple glass slide. The hemocytometer has grids on the slide which will
allow for organized counting of cells. Though not as accurate as a machine, it will be
more accurate than counting without the grid.
Erythrocyte Sedimentation Rate (ESR)
The ESR is a nonspecific indicator of disease that measures the rate of sedimentation
of erythrocytes in anticoagulated blood over 1 hour. If various proteins coat