Test Details
Methodology
Wright stain; microscopic examination of thick and thin peripheral blood smears stained with Romanovsky dye (in particular Giemsa). Thick films are more difficult to interpret but greatly increase sensitivity (by concentrating cells and organisms). Thick smears require considerable experience with malaria, as they increase the number of cells examined in a given time period by a factor of about 12.1
Result Turnaround Time
2 - 4 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Use
Establish the diagnosis of Plasmodium or other parasitic infection; diagnose malarial parasitic infestation of blood; evaluate febrile disease of unknown origin
Limitations
One negative result does not rule out the possibility of parasitic infestation. If protozoal, filarial, or trypanosomal infection is strongly suspected, test should be performed at least three times with samples obtained at different times in the fever cycle.
Footnotes
References
Custom Additional Information
Proper therapy depends on identification of the specific variety of malaria parasite. Release of trophozoites and RBC debris results in a febrile response. Periodicity of fever correlates with type of malaria (see table). Organisms are most likely to be detected just before onset of fever, which is predictable in many cases. Sampling immediately upon onset of fever is the most desirable time to obtain blood. Alternatively, in cases negative by these means but with a strong clinical history, multiple sampling at different times in the fever cycle may prove successful.
Plasmodium Species | Infected RBC Enlarged | Presence of Schüffner Dots | Presence of Maurer Dots | Multiple Parasites per RBC | Parasite With Double Chromatin Dots | Parasite With Sausage- Shaped Gametocytes |
|---|---|---|---|---|---|---|
P vivax | + | + | — | Rare | Rare | — |
P falciparum | — | — | + | + | + | + |
P ovale | ± | + | — | — | — | — |
P malariae | — | — | + | — | — | — |
Specimen Requirements
Specimen
Smears made from fresh whole capillary (fingerstick) blood and/or capillary blood in EDTA (Microtainer™), or 3 to 5 mL fresh whole venous blood in EDTA
Volume
Films (two thin and two thick) or 3 to 5 mL fresh whole venous blood in EDTA
Container
Glass slide, lavender-top (EDTA) tube
Collection Instructions
Air dry
Reference Range
No organisms identified
Storage Instructions
Maintain EDTA whole blood specimen at room temperature for no longer than 24 to 48 hours.
Patient Preparation
Prepare sterile venipuncture site
Causes for Rejection
Specimen clotted; improper labeling
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 008185 | Parasite Exam, Blood | 24429-3 | 008185 | Parasite Exam, Blood | 24429-3 | |
| Order Code | 008185 | |||||
| Order Code Name | Parasite Exam, Blood | |||||
| Order Loinc | 24429-3 | |||||
| Result Code | 008185 | |||||
| Result Code Name | Parasite Exam, Blood | |||||
| UofM | ||||||
| Result LOINC | 24429-3 |