What tests should be done to identify worms?
Tests for worms must be carried out regularly in order to timely identify the disease. The most famous of them is the analysis of feces, which is done before getting a job or a trip to a sanatorium, but this is not the only and not the most reliable way to identify parasites. A combination of tests will give the most accurate answer.
What tests for worms exist
The list of examinations that must 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, aka a blood test for worms. Pros - high accuracy. Cons - reveals only certain stages of parasite development, at other times the result will be questionable;
- Analyzes of other biological media (urine, sputum, duodenal contents, epidermis). Pros - allows you to identify parasites in those localizations that are inaccessible to other analyzes. Cons - associated with significant inconvenience for the patient.
Typically, a patient is prescribed a combination of several tests in order to identify the parasite. The criterion for recovery is a negative ELISA result and several negative results of the study of the biological environment where the worms are detected.
Analysis of feces for worm eggs
Most of the worms live in the intestines, so the most common test for worms is stool testing. He 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. Also, this analysis is taken by people who have been in contact with infected patients, who have eaten untested foods, who have noted characteristic symptoms of worms.
There is no need to specially prepare for the analysis, you can collect feces at any time of the day, but the most indicative is morning feces. Immediately before delivery, you should wash the perineum to avoid urine impurities and discharge from the genitals.
Feces for analysis for worms 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, you need to take a sample from the middle of a portion of feces. The container needs to be filled about a third. You need to deliver it to the laboratory on the same day.
In the laboratory, a specialist examines the feces under a microscope and identifies the eggs of worms in 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 about their presence and type, after which treatment is prescribed.
This is the most common but least accurate worm test. The reason is that there may not be eggs in the portion that has got into the container, despite the fact that there are worms. Therefore, if the patient complains of characteristic symptoms or has been in contact with the source of infection, it is required to undergo 5-6 tests with an interval of 2-3 days. In this case, the likelihood of detecting parasites is significantly increased. Together with the study of feces, other diagnostic procedures are prescribed.
This analysis usually complements stool analysis. The most accurate result is achieved when diagnosing pinworms that lay eggs on the skin surface 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 pinworm).
There is no need to prepare for the analysis for worms, you should not wash the perineum - so it is possible to wash off the eggs of parasites, you need to refrain from bathing or showering the night before. The analysis is done 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 a microscope. It does not detect other helminthiases, except pinworms.
This examination is the least frequently prescribed, as parasites almost never inhabit urine. Situations are possible when pinworms are found in the analysis of urine, but this indicates a violation of the rules for passing 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 still there are indications for testing. In the kidneys and urinary organs, some tropical parasites live, with which a person is "rewarded" by a trip to Asian and African resorts. With the increasing availability of exotic recreation areas, the spread of parasites uncharacteristic for our country is also growing. For this reason, it is advisable to take a urine and blood test for worms after a trip to resorts.
Types of worms found in urine:
- Distomum haematobium;
- Filaria sanguinis hominis;
- Taqnia echinococcus.
Also in the urine there may be eggs of hepatic parasites - echinococcus and flukes.
There are a number of parasites that spend all or part of their lives in the lungs. The symptomatology of their appearance is not typical - catarrhal phenomena develop in the bronchi (inflammation, cough, wheezing). Hemoptysis, pneumonia of unknown origin and other phenomena from the lungs may be noted.
Parasites detected by the sputum worm test:
- Ascaris - in the larval stage they need oxygen;
- Echinococci and alveococci are tissue parasites that live in parenchymal organs, including the lungs;
- Dwarf fluke - lives mainly in the lungs;
- Strongyloidosis, noncatorosis - parasitosis characterized by intestinal localization, the location in the lungs is found as atypical.
In order to collect sputum, no special preparation is required, 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 the 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 up sputum, it is removed from the trachea using a vacuum suction.
It is possible to use medications that improve the discharge of sputum, stimulate its formation to obtain more accurate results of the analysis for worms. In combination with a blood test for worms, it gives very accurate results. Unlike stool testing, eggs are more likely to be found.
ELISA, or blood test for worms - the most accurate method for their determination. Helminths cause a powerful reaction from the immune system - the content of eosinophilic leukocytes increases, the production of immunoglobulins increases, and specific antibodies to parasites appear. It is on their detection that the ELISA method is built.
Antibodies to parasites are extremely specific - they can be unambiguously diagnosed, while they are present in the blood only in the presence of parasites and within 3 weeks after their disappearance.
Blood from a vein is required for analysis. No special training required. The result can be obtained within two days. The accuracy is close to 100%, the specificity of antibodies does not allow for 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. The parasites lay eggs, which pass through the ducts into the intestines. The technique of analyzing the contents of the duodenum for worms allows detecting these diseases much more accurately than analyzing feces.
The material is taken with a duodenal probe on an empty stomach. If the patient has a pronounced gag reflex, pain relief is applied. The procedure is quite unpleasant, therefore, it is resorted to only in those cases when the results of other examinations are doubtful.
When do you need to be tested for worms
Tests for worms should be taken in the following situations:
- The patient is experiencing symptoms of a helminth infection;
- The patient has been in contact with sources of invasion (sick people, untested products, areas with an unfavorable sanitary environment);
- Confirmation is required that the patient is not a source of infection (employment, health records, out-of-town recreation, hospitalization).
How to get tested for worms
To get tested for worms, you need to have a referral from your GP. Most examinations do not require preparation, and if there are nuances, the doctor will explain them when prescribing a study. Indications are required for the doctor to write a referral.
In commercial clinics, you can take the test regardless of the indication. The price varies considerably. The time for obtaining 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.
What helminths can be detected using tests
The analysis for worms detects most types of parasites - intestinal and extraintestinal forms. The most accurate is a blood test for worms, which allows you to identify the parasite.