According to medical statistics, a huge number of people are infected with parasites. Helminths and protozoa very easily penetrate the human body. Often, the invasion is asymptomatic, and infection can only be detected with the help of special studies. What tests for parasites are most often used in modern diagnostics? And how to decipher the results of the examinations? We will consider these issues in the article.
Types of tests
What tests are done for parasites? Most often, if helminthiases and giardiasis are suspected, doctors recommend undergoing the following examinations:
- Fecal analysis. There are various methods for detecting parasites in faeces. Most often, the biomaterial is examined under a microscope. Nowadays, the PCR diagnostic method is also used, which allows you to accurately determine the presence of parasites in the intestines.
- Blood test. This is the most reliable study. It helps to detect antibodies to helminths andprotozoan, as well as the DNA of parasites.
- Analysis of mucus from the anal area. A skin scraping around the rectum is taken for examination and sent for microscopy.
Only a specialist can determine which examinations a patient needs to undergo. The traditional method for detecting helminths is the analysis of feces for eggs of worms. However, not all parasites can be detected in this way. Therefore, at present, a blood test for antibodies to helminths is more often used.
Indications
Doctors will test for parasites if a patient has the following symptoms:
- unreasonable weight loss with a normal diet;
- constant feeling of tiredness;
- irritation and itching in the anal area;
- signs of general intoxication of the body;
- dyspeptic manifestations (diarrhea, nausea, vomiting, bloating);
- skin allergic reactions (itching, rashes);
- sleep disorders;
- decreased immunity;
- drop in hemoglobin;
- inflammation in the urogenital area of unknown etiology.
Such symptoms may indicate the presence of helminths or protozoa in the body.
Research on parasites is carried out not only for the diagnosis of diseases, but also for preventive purposes. A number of such analyzes are required for registration of a medical book. This document is necessary for all people whose activities are related to food, as well as employees of children's institutions and medical personnel.
BIn childhood, helminthiases and giardiasis are especially common. Therefore, each child, upon admission to a kindergarten or school, must be tested for parasites. Pediatricians recommend undergoing such an examination at least once a year in order to detect invasion in time.
Analysis of feces for eggs of worms
This is the most common type of parasite test. It diagnoses the presence of the following types of worms:
- nematode;
- tapeworms;
- flukes.
Material for research should be collected in the morning on an empty stomach. Antibiotics should be stopped 14 days before sampling.
Biomaterial is studied under a microscope and the presence of helminth eggs, larvae and fragments of adult worms is determined. A negative result of the analysis indicates the absence of worm eggs, and a positive result indicates the presence of invasion.
How informative is this study? Often there are cases when the analysis gave negative results, but a person has all the signs of helminthiasis. This suggests that at the time of the delivery of the biomaterial, the parasites had not yet had time to lay their eggs. Therefore, for accurate diagnosis, such an analysis is repeated several times.
Extended fecal examination
Advanced parasite analysis is more informative than conventional microscopic examination. Using PCR diagnostics, the presence of parasite DNA in feces is determined. Such a test shows the presence of helminths at any stage of their life cycle.
The following results can be indicated in the transcript of the analysis:
- Negative. This means that the person has no parasites.
- Positive. Indicates an infestation with parasitic worms. At the same time, the type of helminth must be indicated in the conclusion.
This parasite test has its drawbacks. With its help, it is impossible to detect extraintestinal worms. For example, a person can be infected with tapeworm larvae (cysticercosis). This type of helminth parasitizes in the internal organs and is not found in the feces. In such cases, the presence of parasites can only be detected with the help of a serological blood test.
Analysis of feces for giardiasis
When analyzing for Giardia, feces are examined under a microscope. It is necessary to prepare for such a test in advance. 14 days before the delivery of the material, foods with fiber should be excluded from the diet, as well as antibiotics and enterosorbents should be avoided.
Negative results of the analysis indicate the absence of Giardia in the biomaterial, and positive results indicate the presence of parasites in the feces.
However, false-negative data cannot be ruled out if the patient has not carefully prepared for the study. Therefore, the test for Giardia often has to be repeated. In the first analysis, invasion is detected in 72% of cases. The re-examination accuracy is 90%.
Blood test
Serological blood test for parasites is one of the most accurate diagnostic methods. This test is verysensitive and informative. With its help, you can accurately identify the type of parasite, its localization, and also trace the dynamics of invasion. Such a test is prescribed for suspected helminthic invasions (including extraintestinal ones) and giardiasis.
The study takes blood from a vein. Before donating the biomaterial, the patient is advised to follow the following rules:
- 8 hours before blood sampling, you need to stop eating. Only clean water is allowed to drink.
- Fatty, spicy and fried foods, as well as alcohol should be excluded from the diet the day before the test for parasites.
- Physical and emotional overload should be avoided on the eve of the study.
- 2 weeks before the test, stop taking your medication. If this is not possible, then it is necessary to inform the doctor about the medications taken.
Detection methods
A blood test for parasites is carried out in the following ways:
- Immunoenzymatic. This is the most informative diagnostic method. It allows you to determine the presence of antibodies (immunoglobulins) of various groups to parasites. Using this method, you can not only establish the presence of invasion, but also differentiate the chronic form of helminthiasis from the acute one.
- Method of polydimensional chain reaction. This method helps to accurately identify the causative agent of invasion. PCR can detect the DNA and RNA of parasites. However, such a study does not allow to determine the stage of the disease.
Blood test transcript
What are normalindicators of enzyme immunoassay for parasites? Test results may be as follows:
- IgG and IgM antibodies were not found in the blood. This suggests that the person is he althy and does not have worms and lamblia. This result is normal.
- IgM immunoglobulins are present in the biomaterial. This indicator indicates a recent infection and an acute stage of a parasitic disease.
- IgG antibodies detected. This indicates a chronic form of invasion in remission.
- Both types of antibodies have been detected: IgM and IgG. Such results of the analysis are noted during exacerbation of chronic parasitic pathology.
If the study was conducted by PCR, then the norm is considered a negative result. Such data indicate the absence of DNA and RNA of helminths in the biomaterial.
A positive test result indicates the presence of parasites in the body. The analysis is pretty accurate. It rarely gives false results. Therefore, if DNA of helminths or protozoa was detected during PCR diagnostics, then it is urgent to start treatment.
Musa analysis
What tests are done for parasites if enterobiasis is suspected? Pinworm infestation cannot be detected by standard stool examination. The eggs of these helminths are not found in faeces. Only adults can exit the intestines. But this is a rather rare phenomenon, which is observed only with severe infection.
Therefore, if enterobiasis is suspected, doctors prescribe a mucus test. FROMusing a cotton swab, a smear is taken from the area of \u200b\u200bthe skin located around the rectum. This is the area where pinworms lay their eggs.
Today, a more convenient method of this research is used. A special adhesive tape is used to take the material. It is glued to the area around the anus, and then torn off and handed over to the laboratory.
Deciphering the data from this study is very easy. A negative result indicates the absence of pinworm eggs, and a positive result indicates the presence of infestation.
It is important to remember that only enterobiasis can be diagnosed with a smear. No other helminths can be detected in this way.
Other types of tests
As already mentioned, not all types of helminths and protozoa live in the intestines. They can parasitize in any other organs. In this case, they cannot be detected using microscopy or PCR diagnostics of feces. What tests for parasites should be taken for extraintestinal invasion? The doctor may order the following tests:
- Sputum analysis. It can be used to detect the presence of helminths such as intestinal acne and lung fluke. The life cycle of such worms takes place mainly in the respiratory organs.
- Urine analysis. With the help of such a study, schistosome eggs can be detected. These helminths parasitize in the urinary organs.
- Biopsy studies. Some types of tapeworms form blisters (cysts) in the internal organs. In such cases, a piece of the affected tissue is taken for analysis.
- Research of bile. Helps detect flukes and flukes. These helminths live in the liver and gallbladder.
At the same time, an ELISA blood test is carried out, which helps to determine the presence of antibodies. Such a comprehensive examination makes it possible to identify even those invasions that are difficult to detect by traditional methods, and start treatment in a timely manner.
