AMPATH Lab: Diagnostic Tests For Blood Parasites

Diagnostic Tests for Blood Parasites

Blood parasites are tiny organisms that live in the bloodstream of both humans and animals. Blood parasites can cause severe illnesses and, in some cases, death. Identifying blood parasites can be challenging because the symptoms of infection are often subtle or non-existent in the early stages.
Advanced diagnostic tests for blood parasites aid in identifying these organisms and guiding treatment. Here, we will take a close look at the diagnostic tests available to detect blood parasites and discuss their use, benefits, and limitations.

Blood Films
Blood films are made by smearing blood samples onto microscope slides and then examining them under a microscope. It is one of the easiest and most common diagnostic tests used to check for blood parasites. Blood films are inexpensive, easy to perform, and can be done in any laboratory with appropriate equipment.
However, interpreting blood films can be challenging for inexperienced technicians. Furthermore, blood films can only detect certain blood parasites and can miss some uncommon species. This test is the most time-consuming but remains a vital diagnostic tool.

Serology
Serology is a vital diagnostic test that determines the levels of parasite antibodies in the bloodstream. The test is used in multiple blood parasites, such as Chagas disease. This test is unique because it can evaluate the life cycle stages, enabling physicians to monitor the effectiveness of the treatment.
The disadvantage of serology is that it may take a more extended period than other diagnostic tests to show if the patient is infected by the parasite.

Enzyme-Linked Immunosorbent Assay (ELISA)
ELISA is a common blood test that helps to detect the presence of antibodies produced in response to various infections. ELISA is effective for detecting some blood parasites like trypanosomes and toxoplasmosis. The test is user-friendly, inexpensive, and results can be obtained within a few hours.
However, ELISA tests are less sensitive and specific than PCR tests. It can often result in false negatives or positives depending on the antibodies present in the blood sample.

Polymerase Chain Reaction (PCR)
PCR is a molecular biology technique used to amplify DNA samples. This diagnostic test is highly sensitive, specific, and can identify a broad range of blood parasites. PCR tests can determine parasite species more accurately than blood films. They can detect low parasite concentrations, and results are typically available within a few hours.
The disadvantage of PCR testing is that it can be expensive, and labs require advanced training and equipment. It is not a test that practitioners can perform on-site.

Conclusion:
Blood parasites are responsible for many pathogenic, life-threatening conditions, but diagnosing the infection can be complicated. Many diagnostic tools can help detect blood parasites, including blood films, PCR, ELISA, and serology. Blood films remain the most common diagnostic tool used due to their low cost, but they can miss tiny differences that other diagnostic tools can identify. PCR, on the other hand, is highly sensitive and can identify a broader range of blood parasites, but it can be expensive.

ELISA is cost-effective, user-friendly and can provide quick results. However, it is less sensitive than PCR and can produce both false-positive and false-negative results. Finally, serology can identify the levels of parasite antibodies in the bloodstream and monitor the effectiveness of treatment, but it requires a more extensive period to show results.