What tests should be performed to identify worms?
Tests for worms should be performed regularly to promptly identify disease. The most famous is the analysis of feces, which is performed before finding a job or a trip to a sanatorium, but this is not the only and not the most reliable way to identify parasites. The most accurate answer will be given by a combination of tests.
What tests exist for worms
The list of exams to be taken to identify parasites is quite long.
The main ones are:
- Analysis of feces, also known as worm eggs, is the most common method. Advantages: massive use, no need for complex equipment. Minus - lack of accuracy;
- ELISA, also known as a blood test for worms. Pros: high precision. Cons - reveals only some stages of the development of the parasite, at other times the result will be questionable;
- Analysis of other biological means (urine, sputum, duodenal contents, epidermis). Pros: they allow you to identify parasites in those locations inaccessible to other analyzes. Cons: associated with significant discomfort for the patient.
Typically, a patient is prescribed a combination of several tests to identify the parasite. The criterion for recovery is a negative ELISA result and several negative results of the study of the biological environment in which the worms are detected.
Analysis of feces for worm eggs
Most worms live in the intestines, so the most common test for worms is the stool test. It is prescribed for routine medical examinations for adults and children, before being sent to a sanatorium or children's camp, as part of a health book, during hospitalization. In addition, this analysis is taken by people who have been in contact with infected patients, who ate untested foods, who noticed symptoms characteristic of worms.
It is not necessary to prepare specifically for the analysis, it is possible to collect stool at any time of the day, but the most indicative is the morning stool. Immediately before delivery, the perineum must be washed to avoid urinary impurities and secretions from the genitals.
Stools for worm analysis are collected in a special container. It is sealed and a special spoon is attached to collect the material. To collect the most informative part of the material, it is necessary to take a sample from the center of a portion of stool. The container should be filled about one third. You have to deliver it to the lab the same day.
In the laboratory, a specialist examines the stool under a microscope and identifies the worm eggs inside it. Most of them have a characteristic shape that allows you to accurately determine the type of worm. Based on the results of the analysis, a conclusion is issued about the absence of eggs or their presence and type, after which treatment is prescribed.
This is the most common but least accurate test worm. The reason is that there may not be any eggs in the portion that went into the container, despite the fact that there are worms. Therefore, if the patient complains of characteristic symptoms or has come into contact with the source of the infection, it is necessary to undergo 5-6 tests with an interval of 2-3 days. In this case, the likelihood of detecting parasites is significantly increased. Along with the study of feces, other diagnostic procedures are prescribed.
Skin scraping
This analysis usually complements the stool analysis. The most accurate result is obtained when diagnosing pinworms, which lay eggs on the surface of the skin near the anus. Indications for such an analysis are routine examination of children and adults, registration of a child in a kindergarten, school, camp or sanatorium, hospitalization of children and adults, suspicion of pinworm infection (itching in the anus, digestive disorders, contact with sick people). Most often, children suffer from this disease, which explains the name of the worm (children's pinworms).
It is not necessary to prepare for the analysis for worms, you should not wash the perineum - so it is possible to wash off the parasite eggs, you must refrain from taking a bath or shower the night before. The analysis is performed in the morning. A special film is used that collects material from the skin of the intergluteal fold. The study is also carried out under the microscope. It does not detect other helminthiases, except pinworms.
Urinalysis
This test is the least prescribed, as parasites almost never populate the urine. Situations are possible when pinworms are found in urinalysis, but this indicates a violation of the rules for the passage of the analysis: parasites and their eggs enter the container from the skin of the perineum. Most often, this situation occurs in girls, less often in boys.
But there are still indications for the test. Some tropical parasites live in the kidneys and urinary organs, which a person is "rewarded" by a trip to Asian and African locations. With the growing availability of exotic recreational areas, the spread of parasites not characteristic of our country is also growing. For this reason, it is advisable to do a urine and blood test for worms after a trip to the resorts.
Types of worms found in urine:
- Trichomonas;
- Distomum haematobium;
- Filaria sanguinis hominis;
- Taqnia echinococcus.
Also in the urine there may be eggs of liver parasites: echinococcus and flukes.
Sputum Analysis
There are a number of parasites that spend all or part of their life in the lungs. The symptomatology of their appearance is not characteristic: catarrhal phenomena develop in the bronchi (inflammation, cough, wheezing). Hemoptysis, pneumonia of unknown origin and other pulmonary phenomena may be noted.
Parasites detected by sputum worm test:
- Ascaris: in the larval stage they need oxygen;
- Echinococci and alveococci are parasites of tissues living in the parenchymal organs, including the lungs;
- Dwarf flounder - lives mainly in the lungs;
- Strongyloidosis, noncatorosis - parasitosis characterized by intestinal localization, the location in the lungs is found as atypical.
No special preparation is required to collect sputum, but it is advisable to brush your teeth and take the material in the morning. Before that, it is useful to drink plenty of fluids - this improves expectoration of sputum. The collection container must be clean, but not necessarily sterile: bacteria do not play a role in the diagnosis. In this case, both the parasites themselves and their eggs are detected. If the patient is unable to cough with phlegm, it is removed from the trachea by vacuum suction.
It is possible to use drugs that improve sputum discharge, stimulate its formation to obtain more accurate results of the analysis for worms. In combination with a blood test for worms, it provides very accurate results. Unlike the stool test, eggs are more likely to be found.
Blood test
ELISA, or blood test for worms, is the most accurate method of determining them. Helminths cause a powerful reaction of the immune system: the content of eosinophilic leukocytes increases, the production of immunoglobulins increases, and specific antibodies against parasites appear. It is on their discovery that the ELISA method is built.
Antibodies against parasites are extremely specific: they can be diagnosed unequivocally, while they are present in the blood only in the presence of parasites and within 3 weeks of their disappearance.
Blood from a vein is needed for the analysis. No special training is required. The result can be achieved within two days. The accuracy is close to 100%, the specificity of the antibodies does not allow an erroneous result. The criterion for recovery is a negative result one month after treatment.
Analysis of duodenal contents
The ducts of the bile ducts and pancreas open into the duodenum. These organs are often affected by echinococcosis and opisthorchiasis. Parasites lay eggs, which pass through the ducts into the intestine. The technique of analyzing the contents of the duodenum for worms allows you to detect these diseases much more accurately than the analysis of feces.
The material is collected with a duodenal probe on an empty stomach. If the patient has a pronounced gag reflex, pain relief is applied. The procedure is rather unpleasant, so it is resorted only in those cases where the results of other examinations are doubtful.
When you need to be tested for worms
Tests for worms should be performed in the following situations:
- Patient has symptoms of a helminth infection;
- The patient has been in contact with sources of invasion (sick, untested products, areas with an unfavorable health environment);
- Confirmation is required that the patient is not a source of infection (work, medical records, out-of-town recreation, hospitalization).
How to test for worms
To be tested for worms, you need to have a referral from your GP. Most exams do not require preparation, and if there are nuances, the doctor will explain to you when prescribing a study. Directions are needed for a doctor to write a referral.
In commercial clinics, an analysis can be performed regardless of indication. The price varies greatly. The time to obtain the results of feces and scrapings is about a week, the analysis of urine, sputum, blood is about 2 days, depending on the workload of the laboratory.
Which helminths can be detected using the tests
The analysis for worms allows you to identify most types of parasites: intestinal and extraintestinal forms. The most accurate is a blood test for worms, which allows you to identify the parasite.