Parasitic infections can cause a wide range of health problems in humans and animals, from mild discomfort to severe and life – threatening conditions. As a laboratory testing supplier, we play a crucial role in providing accurate and reliable diagnostic solutions for these infections. In this blog, we’ll walk you through how laboratory tests for parasitic infections are performed. Laboratory Testing
1. Sample Collection
The journey of diagnosing a parasitic infection begins with sample collection. The type of sample required depends on the likely location of the parasite in the body.
1.1 Stool Samples
Stool samples are commonly used for detecting intestinal parasites such as Giardia lamblia, Entamoeba histolytica, and various helminths like Ascaris lumbricoides and Trichuris trichiura. A patient is usually provided with a clean, wide – mouthed container and instructions on how to collect a fresh stool sample. It’s important that the sample is not contaminated with urine or water. The sample should be collected in the morning if possible, as some parasites may shed their eggs or cysts more readily during this time.
1.2 Blood Samples
Blood is used to detect parasites that circulate in the bloodstream, such as Plasmodium species (which cause malaria), Trypanosoma species (responsible for African sleeping sickness and Chagas disease), and Leishmania species. A phlebotomist uses a sterile needle to draw blood from a vein, typically in the arm. The amount of blood collected varies depending on the specific test, but it’s usually a few milliliters.
1.3 Tissue Samples
In some cases, a tissue sample may be necessary to diagnose a parasitic infection. This can include skin biopsies for detecting parasites like Onchocerca volvulus, which causes river blindness. A small piece of the affected tissue is removed under local anesthesia and sent to the laboratory for analysis.
1.4 Urine Samples
Urine samples can be useful for detecting parasites such as Schistosoma haematobium, which can affect the urinary system. A mid – stream urine sample is usually collected in a clean container.
2. Sample Transport and Storage
Once the samples are collected, they need to be transported and stored properly to ensure the integrity of the parasites and the accuracy of the tests.
Stool samples should be transported to the laboratory as soon as possible, preferably within an hour. If this is not possible, they can be stored in a refrigerator at 2 – 8°C for up to 24 hours. However, some preservation methods require the addition of fixatives such as formalin or PVA (polyvinyl alcohol) to the stool sample to preserve the parasites and their structures for a longer period.
Blood samples are usually collected in tubes containing anticoagulants to prevent clotting. They should be kept at room temperature and transported to the laboratory within a few hours. If there is a delay in testing, they can be stored at 2 – 8°C for a limited time.
Tissue samples are placed in appropriate fixatives, such as formalin, and transported to the laboratory. They can be stored in the fixative for an extended period until further processing.
Urine samples should be transported to the laboratory within an hour of collection. If this is not feasible, they can be refrigerated at 2 – 8°C for a short time.
3. Laboratory Processing
3.1 Direct Microscopic Examination
One of the most common methods for detecting parasites is direct microscopic examination.
For stool samples, a small amount of the sample is mixed with a drop of saline or iodine solution on a glass slide and covered with a coverslip. The slide is then examined under a microscope at low and high magnification. This method can detect the presence of parasite eggs, cysts, trophozoites, or larvae. For example, the characteristic shape and size of Ascaris eggs can be easily identified under the microscope.
Blood smears are prepared for the detection of blood – borne parasites. A thin smear is made by spreading a small drop of blood on a glass slide and allowing it to air – dry. It is then stained with a special stain, such as Giemsa stain, to make the parasites visible. In the case of malaria, the different stages of Plasmodium parasites, such as the ring forms, trophozoites, and schizonts, can be seen in the red blood cells.
Tissue samples are processed through a series of steps, including dehydration, clearing, and embedding in paraffin wax. Thin sections are then cut using a microtome and stained with hematoxylin and eosin (H&E) or other special stains. This allows the pathologist to examine the tissue for the presence of parasites and any associated pathological changes.
3.2 Concentration Techniques
In some cases, the number of parasites in the sample may be too low to be detected by direct microscopy. Concentration techniques are used to increase the likelihood of finding parasites.
For stool samples, sedimentation and flotation methods are commonly used. Sedimentation involves allowing the stool sample to settle in a container, and then the sediment at the bottom is examined. Flotation methods use a solution with a high specific gravity, such as zinc sulfate or Sheather’s sugar solution. The parasites float to the surface, and a thin film is taken from the surface for microscopic examination.
3.3 Immunological Tests
Immunological tests are based on the detection of antibodies or antigens related to the parasite.
Antibody – based tests, such as enzyme – linked immunosorbent assays (ELISA), can detect the presence of antibodies produced by the host’s immune system in response to a parasitic infection. For example, ELISA can be used to detect antibodies against Toxoplasma gondii, a parasite that can cause toxoplasmosis.
Antigen – based tests detect the presence of parasite – specific antigens in the sample. For instance, rapid diagnostic tests (RDTs) for malaria are antigen – based tests that can detect the presence of Plasmodium antigens in the blood. These tests are quick and easy to perform, making them suitable for use in resource – limited settings.
3.4 Molecular Tests
Molecular tests, such as polymerase chain reaction (PCR), are becoming increasingly important in the diagnosis of parasitic infections. PCR can amplify specific DNA or RNA sequences of the parasite, allowing for highly sensitive and specific detection.
In the case of Cryptosporidium parvum, PCR can detect the parasite’s DNA in stool samples, even when the number of oocysts is very low. This is particularly useful for detecting cryptosporidiosis in immunocompromised patients, where the accurate diagnosis is crucial for appropriate treatment.
4. Quality Control and Result Reporting
Quality control is an essential part of laboratory testing for parasitic infections. Our laboratory implements a comprehensive quality control program to ensure the accuracy and reliability of the test results.
This includes using control samples with known concentrations of parasites or parasite antigens/antibodies. These control samples are run alongside the patient samples to verify the performance of the testing methods. Regular calibration of the laboratory equipment, such as microscopes and PCR machines, is also carried out to ensure accurate measurements.
Once the tests are completed, the results are reported in a clear and concise manner. The report includes information about the patient, the type of test performed, the result, and any interpretive comments. For positive results, the report may also include information about the recommended treatment and follow – up tests.
5. The Role of Our Laboratory Testing Supply
As a laboratory testing supplier, we understand the importance of providing high – quality products and services. We offer a wide range of tools and reagents for the diagnosis of parasitic infections.
Our product portfolio includes microscope slides, stains (such as Giemsa, H&E, and iodine), fixatives (formalin, PVA), and diagnostic kits (ELISA, RDTs, PCR kits). Our products are designed to meet the highest standards of quality and performance, ensuring accurate and reliable test results.
In addition to our products, we also provide technical support and training to our customers. Our team of experts is available to answer any questions you may have about sample collection, test performance, or result interpretation.
Certification and Compliance If you are a laboratory or healthcare provider looking for reliable laboratory testing solutions for parasitic infections, we invite you to get in touch with us. Our dedicated sales team is ready to discuss your specific needs and provide you with a customized solution that meets your requirements. Whether you need a small quantity of reagents for a pilot project or a large – scale supply for a high – volume laboratory, we can accommodate your needs. Reach out to us to start a conversation about how we can partner to improve the diagnosis of parasitic infections in your setting.
References
- Garcia, L. S. (2016). Diagnostic medical parasitology. ASM Press.
- Mahmoud, A. A. F., & Warren, K. S. (Eds.). (2019). Tropical medicine and parasitology: anemia in parasitic diseases. Springer.
- Zijlstra, E. E., & El Tahir, K. E. (2012). Immunology of human African trypanosomiasis. Parasite Immunology, 34(7), 311 – 319.
Verittek Standards Co., Ltd.
As a professional laboratory testing service provider in China, we help clients improve overall product quality and stability by providing third-party inspection services. If you have any enquiry about cooperation, please feel free to email us.
Address: Room 1002, Building 1, Tian’an Industrial Building, Panyu Energy Saving Technology Park, No.555 North Panyu Avenue, Donghuan Street, Panyu District, Guangzhou City, China.
E-mail: sales@verittek.com
WebSite: https://www.verittek.com/
