What tests should be performed to identify worms?
Testing for worms should be done regularly to identify the disease in a timely manner. The most famous of these is the analysis of feces, which is done before finding a job or a trip to a sanatorium, but it is not the only and not the most reliable way to identify parasites. . The most precise answer will be given by a combination of tests.
What tests for worms exist
The list of exams to be performed to identify parasites is quite long.
The main ones are:
- Testing feces, also known as worm eggs, is the most common method. Advantages - massive use, no need for complex equipment. Minus - lack of precision;
- ELISA, aka blood test for worms. Advantages - high precision. Disadvantages - only reveals certain stages of the development of the parasite, at other times the result will be questionable;
- Analyzes of other biological media (urine, sputum, duodenal content, epidermis). Benefits - allows you to identify parasites in locations that are not available for further analysis. Disadvantages - associated with significant inconvenience for the patient.
Typically, a patient is ordered a combination of several tests to identify the parasite. The criterion for recovery is a negative ELISA result and several negative results from the study of the biological environment where the worms are detected.
Fecal analysis 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 a children's camp, as part of a health record, during hospitalization. In addition, this analysis is carried out by people who have been in contact with infected patients, who ate untested food, who noted symptoms characteristic of worms.
It is not necessary to prepare specially for the analysis, you can collect the feces at any time of the day, but the most indicative is the feces in the morning. Immediately before childbirth, you should wash the perineum to avoid urinary impurities and discharge from the genitals.
Feces 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, you need to take a sample from the middle of a part of feces. The container should be about a third full. You must deliver it to the lab the same day.
In the laboratory, a specialist examines the feces under a microscope and identifies worm eggs 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 drawn about the absence of eggs or 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 any eggs in the part that entered 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 necessary to undergo 5-6 tests with an interval of 2-3 days. In this case, the probability of detecting parasites is greatly increased. Along with the study of feces, other diagnostic procedures are prescribed.
Skin scratching
This test usually complements the stool test. 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 a routine examination of children and adults, enrollment of a child in a kindergarten, school, camp or sanatorium, hospitalization of children and adults, suspected infection with pinworms (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 of worms, you should not wash the perineum - therefore it is possible to wash the eggs of parasites, you should refrain from bathing or showering thestandby. The analysis is done in the morning. A special film is used which collects the material from the skin of the intergluteal fold. The study is also carried out under a microscope. It does not detect other helminthiasis, except pinworms.
Urinalysis
This test is prescribed the least frequently, as the parasites almost never live in the urine. Situations are possible when pinworms are found in the urine analysis, but this indicates a violation of the rules for successful analysis - the parasites and their eggs enter the container through the skin of the perineum. Most often this situation occurs in girls, less often in boys.
But there are still hints for testing. Some tropical parasites live in the kidneys and urinary organs, which a person is "rewarded" with a trip to Asian and African resorts. With the increasing availability of exotic recreation areas, the spread of pests unusual for our country is also increasing. For this reason, it is advisable to take 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.
There may also be eggs of liver parasites in the urine - echinococcus and fluke.
Sputum analysis
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 pulmonary phenomena may be noted.
Parasites detected by 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 primarily in the lungs;
- Strongyloidosis, noncatorosis - parasitosis characterized by intestinal localization, localization in the lungs is considered 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 - it improves the expectoration of sputum. The collection container should be clean, but not necessarily sterile - bacteria play no role in the diagnosis. In this case, the parasites themselves and their eggs are detected. If the patient is unable to cough up phlegm, it is removed from the trachea by vacuum aspiration.
It is possible to use drugs that improve the discharge of sputum, stimulate its formation to achieve more accurate results of the analysis of worms. In combination with a blood test for worms, it gives very accurate results. Unlike stool tests, eggs are more likely to be found.
Blood test
ELISA, or blood test for worms - the most accurate method for their determination. Helminths cause a powerful reaction of the immune system - the content of eosinophilic leukocytes increases, the production of immunoglobulins increases, and specific antibodies against the parasites appear. It is on their detection that the ELISA method is built.
Antibodies to parasites are extremely specific - they can be diagnosed without ambiguity, whereas they are only present in the blood in the presence of parasites and within 3 weeks of their disappearance.
Blood from a vein is required for analysis. No special training required. The result can be obtained within two days. The precision 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 the treatment.
Analysis of duodenal content
The ducts of the bile ducts and the pancreas lead into the duodenum. These organs are often affected by echinococcosis and opisthorchiasis. The parasites lay eggs which pass through the ducts in the intestines. The technique of analyzing the content of the duodenum for worms can detect these diseases much more precisely than analyzing feces.
The material is collected with a fasting duodenal catheter. If the patient has a pronounced gag reflex, pain relief is applied. The procedure is rather unpleasant, therefore, it is used only in cases where the results of other examinations are doubtful.
When should you be tested for worms
Testing for worms should be performed in the following situations:
- The patient has symptoms of a helminth infection;
- The patient has been in contact with sources of invasion (sick people, untested products, areas with unfavorable sanitary environment);
- Confirm that the patient is not a source of infection (employment, health records, out of town recreation, hospitalization).
How to get tested for worms
To be tested for worms, you must have a referral from your GP. Most exams do not require preparation, and if there are nuances, the doctor will explain them when ordering a study. Indications are needed for a doctor to write a recommendation.
In commercial clinics you can perform an analysis regardless of the indication. The price varies considerably. The time to get the results of feces and scrapings is about a week, the analysis of urine, sputum and blood is about 2 days, depending on the workload of the laboratory.
Which helminths can be detected using tests
Analysis of worms can identify most types of parasites - intestinal and extra-intestinal forms. The most accurate is a blood test for worms, which allows you to identify the parasite.