Examination of smears of prints. Preparation of smears and their fixation Interpretation of the histological conclusion

17.05.2020

A drop of sterile water is applied to a clean, fat-free glass slide, which should spread evenly without breaking into droplets. In this case, very large drops of water should not be applied to the glass. A little test material is added to the drop and it is thoroughly mixed, evenly distributing it in a thin layer. In the manufacture of smears from liquid nutrient media, the material taken by the loop is not diluted with water. Smears from media containing sugar are prepared by adding a small drop of sterile skim water or egg white to a drop of the test liquid.
Prepared smears are usually dried at room temperature. To speed up drying, preparations can be warmed up by holding a glass slide with smears on their upper side in warm air high above the burner flame (Fig. 41) using Cornet's tweezers.

Careful drying prevents the rapid and coarse precipitation of bacterial protoplasmic proteins and thereby preserves their structure. Properly dried preparations are well fixed. Fixation provides a better adhesion of the smear to the glass and makes it more susceptible to staining. The most common and suitable in almost all cases is the method of fixing smears with heat. To do this, the glass with the preparation smear up is carried out three times through the flame of an alcohol or gas burner. The temperature of the heated glass should be such that when it comes into contact with the skin of the back of the hand, a slight burn would be felt. You should not overheat the glass, as this spoils the smear and greatly changes the structure of the bacteria. Heat fixation is used in the study of the relationship of bacteria to Gram stain, the detection of acid resistance and the content of lipids. This method is completely unsuitable for studying the internal structure of bacteria. In such cases, various chemical substances. The most used are the following tricks commits:
- 95% ethyl alcohol within 10-20 minutes, if the alcohol is weaker, then the fixation time is lengthened; a mixture of equal volumes of ethyl alcohol and ether (Nikiforov's liquid); a few drops of the mixture are applied to the preparation and allowed to evaporate;
- a mixture of ethyl alcohol and formalin (formalin 5 ml, alcohol 95 ml) - 5-10 minutes;
- anhydrous methyl alcohol for 2-3 minutes; alcohol is drained, and the drug is dried;
- vapors of formalin or acetic acid - 5–10 min; vapors of 1–2% osmic acid solution; the drug is placed on a stand in a closed bottle with osmic acid and incubated for 3-5 minutes;
- Carnoy's liquid (96° ethyl alcohol - 60 ml, chloroform - 30 ml, glacial acetic acid - 10 ml) - 15 min;
- acetone for 5 minutes;
- 10% silver nitrate solution - 10 min;
- 1% mercuric chloride solution for 10–15 minutes, after which the preparation is washed with a solution of common salt and water;
- Bouin's liquid of the following composition: saturated aqueous solution picric acid - 75 ml, undiluted formalin - 25 ml and glacial acetic acid - 5 ml.
Preparing prints
Due to the increased interest in last years to study fine structure bacteria have been developed a variety of effective ways fixation of bacteria deposited on glass in the form of imprints. In such an imprint preparation, the mutual arrangement of cells in the bacterial lawn is more or less exactly preserved. The imprint method consists in the fact that a block is cut out of agar in a Petri dish with bacteria seeded on it and transferred to a glass slide. Then a defatted glass slide is taken and applied to the surface of the block inoculated with bacteria, thus obtaining the first imprint. Imprints are made until the layer of bacteria on the block is depleted, placing them from left to right, starting from the left short edge of the glass. The prints are then allowed to dry and the slide is placed in Carnoy's liquid to fix. Good results gives also the fixation of osmic acid. Other methods of imprint fixation are described in the literature.

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Everyone is used to the fact that when a man is examined by a venereologist and a urologist for sexually transmitted infections, they take a swab from the urethra and a blood test for STIs. But it happens that other methods of taking material for research play a leading role in the diagnosis.

Such methods include a smear-imprint from the head and skin foreskin male penis.

The inflammatory process is not always present in the urethra, and the infection accordingly enters and multiplies not only in it. At various types bacterial and fungal balanoposthitis, genital herpes, syphilis, phimosis, papillomavirus infection, we observe the pathological process on the skin of the penis and its head.

Accordingly, it would be more natural to take smears and scrapings directly from the lesion, and then examine the blood and urethra.

The material sampling technique for smear-imprint analysis is quite simple. There are 4 types of diagnostics in which this method is used:

A clean glass slide is simply applied to the inflamed area on the skin of the penis. And with the help of a small sliding movement, the surface layers of the epithelium with the STI pathogens present in it are applied to the glass. Next, the preparation is dried, stained and microscoped. So you can determine the number of leukocytes, mucus, epithelium, fungi and bacteria from the glans penis. Moreover, this smear-imprint is made quickly enough. Half an hour later, the answer is ready.
With the help of a urogenital probe, from the surface of the head, foreskin, from some rashes and sores, deeper layers of the epithelium are scraped off and placed in an Ependorf tube for PCR analysis. This is how herpes, syphilis, HPV, candida, gardnerella and other pathogens of sexually transmitted diseases of the skin of the head and foreskin of the male penis are determined.
If, with a sterile cotton swab, remove plaque or mucus from the head and place the material in a transport or nutrient medium, then it is possible to inoculate the flora and sensitivity to antibiotics of the microflora that caused inflammation of the skin of the penis.
In the presence of long non-healing sores, erosions, spots and a suspicion of a malignant process, a scraping is taken for atypical cells - a cytological examination.

The smear-print analysis is probably the most painless method for studying the male reproductive system. Therefore, there is no reason to delay contacting a urologist and venereologist to pass this analysis when some spots and other pathological rashes appear on the skin of the head and foreskin of the penis.

The cost of this type of smear is 900 rubles. The express laboratory is open daily. Based on the results of the analysis, you will definitely be consulted by a specialist in male diseases and STIs.

A smear imprint is a study that, unlike a standard smear, not everyone has heard of. Today, this diagnostic method is actively used by gynecologists, urologists, and oncologists. As well as some other experts.

How the taking of smears of prints is carried out, patients are interested in their attending physicians.

What are the types of this analysis?

How to properly prepare for taking a fingerprint and how is decryption carried out?

Smear imprint: features of material sampling

Smear imprint: what is this study

Many patients are often interested in what it is - the study of smears of prints , and what are the features of this study. In fact, the study is quite simple. All that needs to be done is to attach the organ to be examined to the glass slide. Then, when the imprint is obtained, the resulting material is stained with a special solution and studied under a microscope.

Interestingly, fingerprint smears are used not only for making diagnoses in the medical field. They are widely used in forensic medical examination, microbiology, pathological anatomy. Such a study has become widely used only in recent years. And even then, not all patients still know what is meant by this analysis.

How to properly prepare for it and what are the types of examination.

Varieties of smear imprint

Today, there are several options for taking a smear of a print. Patients ask their doctors what types of research are available.

There are several options:

The study can be applied to diagnose various infections on the genitals. Its implementation is recommended for various suspicions of infectious processes of both a specific and non-specific type. A study from an ulcer can be performed, for example, with. With this pathology, an unpleasant, painful ulcer appears on the genitals, especially in men. An imprint is taken from it, so that later, with dark-field microscopy, pale treponemas can be detected.

Another diagnostic option is the detection of herpes infection. It is especially effective after erosion is formed after the breakthrough of papules.

Head smear

The imprint is recommended for men who suffer from non-specific infections. Especially often it should be carried out with balanoposthitis or balanitis. With the help of the study, it is possible to identify non-specific pathogens, such as coccus coli, E. coli, fungi.

Smear imprint with cervical erosion

Women are advised to take the test if they have erosion on the cervix. This is necessary to make sure that there are no signs of malignant degeneration in the organ. If such signs are found, the fair sex is recommended to contact an oncologist.

Indications for performing a smear print

A smear imprint of the head, from the cervix or other parts can be performed for various indications. Most often, the doctor directs the patient to this study if there is a suspicion of an infectious process.

Symptoms with which a patient may receive a referral for analysis are as follows:

Everyone knows that a swab from the urethra - painful procedure for the stronger sex. In women, this procedure is somewhat easier, but still unpleasant. A smear imprint differs from a smear from the urethra in its complete painlessness.

True, unfortunately, the indications for performing these procedures are not the same, and therefore it is most often impossible to replace one with the other.

The execution technique is very simple. The man is asked to undress from the waist down. Then, using a special brush, biological material is collected. It is especially important to collect a sufficient amount of material, but not to overdo it.

If there is not enough material, it will not be possible to get at least some results. An excess of biomaterial can lead to false positive or false negative results.

The biological material obtained with a brush is applied to a glass slide. And they are fixed by special methods for examination with a microscope. Or placed in a special test tube.

The test tube or glass is sent to the laboratory, where further studies are carried out if necessary. As an analogy for taking material with a brush, you can put the penis on a slide or carefully collect the secretions with a slide. But, according to doctors, using a brush is a more correct option.

How smears are prepared

Preparing a smear of an imprint is a task that a competent doctor or laboratory assistant should perform. The fact is that it is not enough just to apply biological material to a glass slide. It also needs to be fixed correctly.

If the biomaterial is not fixed, then examine it with a high degree reliability fails. Various dyes can be used for coloring. The most commonly used Gram stain. With its help, normal and pathological microflora is detected, which can harm the patient.

True, it should be borne in mind that the print does not allow the detection of viruses, since it is impossible to stain them. But with the help of this diagnostic method, it is possible to detect not only pathogenic microorganisms, but also. Candida is the most commonly diagnosed.

Smear imprint: basic preparation rules

Neither a man nor a woman can come for an examination and immediately get reliable results by passing an analysis just like that. It is necessary to carry out a minimum preparation, which will allow obtaining reliable data.

If the preparation is carried out correctly, then the results will be the most accurate and reliable. If the patient violates the recommendations, it is likely that he will have to undergo a diagnostic study again. Since the doctor will be able to question their reliability.

Interpretation of smear results

Deciphering the results of a smear print should be carried out by a doctor. Only a medical professional can reliably evaluate the results. Focusing not only on what is written in the certificate, but also on how the patient feels. In fact, only thanks to the doctor can you separate reliable results from false positives and false negatives.

When evaluating the results, first of all, pay attention to:

the presence of bacteria in the smear, which can be both pathogenic and normal;
detection in the results of pathogenic fungi that can adversely affect the health of the patient;
the presence of epithelium, mucus and other particles that can be evaluated both positively and negatively.

Patients are not recommended to independently decipher the analyzes, even if it seems that this can be done easily. You must bring the results to the doctor. So that he evaluates the results and, relying on them and objective data from the study, he can make an accurate diagnosis.

Smear imprint: what to do if the results are bad

If the impression smear results are poor, the patient should not panic in the first place. It is necessary, by visiting a doctor, to get a referral from him for re-analysis. In case of positive results, it is necessary to double-check the results.

To rule out false-positive diagnoses. Further, after repeated results are obtained, if they are still positive, you need to see a doctor.

The healthcare worker will be able to:

give recommendations regarding the passage of additional studies in order to make a final diagnosis;
make recommendations regarding proper treatment diseases;
monitor the course of therapy and prescribe control diagnostics in order to understand how effective the treatment is in the end;
if necessary, change the approach to treatment in order to obtain reliable results.

If a patient has a sexually transmitted infection, this may lead to a violation reproductive function. It is infertility that basically makes people go to the doctor for a diagnosis. Which, among other things, may include the execution of a smear of the print.

Often patients are interested in where they can take a smear cytology or an alternative to this study. You can contact both the state dermatovenerological dispensary and a private clinic if necessary. You can donate biomaterial for research free of charge. If you undergo diagnostics at the place of residence on the recommendation of a doctor. Also for a fee.

Passing a smear print is a good diagnostic method that allows you to make a diagnosis in many cases. If this approach is not enough to determine the disease, the doctor will be able, after evaluating the results, to select the most optimal options for clarifying diagnostics. And then choose the methods of therapy that will give positive effect and monitor the progress of treatment.

If you need to make a smear print, contact competent venereologists and gynecologists.

A smear-imprint can be used to diagnose infectious lesions of the genital organs. They are prescribed for suspected specific or non-specific infections.

Most infectious processes genitourinary system located in the urethra. Therefore, the doctor takes a scraping from the urethra and checks it with one method or another (, PCR, seeding tank). But not for all infections, the urethra becomes the main affected area.

Venereal diseases, in which the mucous membrane of the genital organs can be the entrance gate:

syphilis;
genital herpes.

In addition, in severe cases of herpes with the formation of ulcerations, a smear-imprint can be taken. It allows you to differentiate this infection from other pathologies: autoimmune, oncological and other pathologies.

Smear-imprint of the head of the penis

Nonspecific infectious processes can also be the reason for the appointment of the study.

A smear-imprint of the head is taken with balanitis or balanoposthitis. This is an inflammation of the head of the penis and foreskin.

The impression smear is stained and examined under a microscope. In this way, some pathogens can be detected: coccal flora, E. coli, fungi of the genus Candida.

If a herpetic origin of balanoposthitis is suspected, smears-prints can be taken from the formed vesicles. They are examined to identify Tzank cells. These are giant multinucleated cells that form with genital herpes.

Research is possible only with a vesicular form of infection.

Imprint smear for cytological examination

Cytological examination involves the determination of atypical cells in the clinical material, indicating cancer. For this, clinical material obtained directly from the focus of the oncological process is used.

The doctor can take smear-imprint from a tumor of the genital organs or skin. It is examined under a microscope.

The purpose of diagnosis: morphological assessment of the cellular composition. The number of nuclei, the size and shape of cells, the nucleus-cytoplasmic ratio and other criteria are determined. The main indication for cytological examination is a suspicion of cancer.

But diagnostics also allows you to identify other, non-tumor pathological processes.

Preparing for a smear test

Preparation for taking a smear depends on the purpose of the diagnosis. If there is a suspicion of infectious processes, the doctor usually requires not to use antiseptics and antibacterial drugs. They can reduce the concentration of the pathogen in the clinical material, which will lead to a false negative result of the study.

The area where the swab will be taken should not be washed. If necessary, do not use soap and other hygiene products.

Immediately before taking a smear-print, it may be necessary to remove fibrinous deposits, open vesicles or other morphological elements of the skin. How is a smear-imprint studied for the presence of bacteria?

Smear-imprint from the genitals studied under a microscope.

Clinical material is placed on a fat-free glass slide. Dry it at room temperature.

Fixation of the drug is carried out by various methods, for example:

heat (least effective method);
alcohol with formalin;
95% ethyl alcohol;
methyl alcohol;
vapors of acetic acid and formalin;
sublimate alcohol, etc.

Different laboratories use different methods.

Special solutions for fixation have been developed, which are mixtures of several chemical compounds. The better the solution, the better it is possible to preserve the structure and arrangement of all cells in the smear, including bacterial cells. After fixation, staining is carried out. For this, different methods are used, depending on the purpose of the study.

Coloring is indicative and differential. Among the differential stains, Gram stain is more common.

Where to take tests?

If you need research, please contact our clinic. We have everything available modern methods diagnostics of pathological processes. Testing for infections and cytology.

Smear-imprint will be taken by an experienced specialist in compliance with all the rules of asepsis and antisepsis, so as not to infect the infection.

The medical professional will do everything possible to ensure that the procedure delivers a minimum of discomfort. Analyzes will be carried out as soon as possible. After completing them, you will receive advice from an experienced dermatologist, venereologist or other specialist.

If you need to painlessly take a smear print, contact the author of this article - a venereologist in Moscow with 15 years of experience.

Exercise 1. Cytological analysis of purulent exudate.

Equipment: glass slides, microscopes; sterile cotton swabs; thermostat; rectified alcohol (65 ml); absolute methyl alcohol (65 ml); Romanovsky-Giemsa paint (120 ml); immersion oil (6 ml); experimental animals with a purulent wound.

Statement of experience. The cytological picture of the inflammatory exudate is studied when receiving wound prints according to M. P. Pokrovskaya and M. S. Makarov. In a surgical clinic, a sick animal with a wound surface covered with purulent exudate is selected in advance.

In the usual way, as well as for hematological studies, glass slides are prepared. During laboratory studies, well-washed and fat-free glass slides are dipped in alcohol (96%), then removed, the remaining alcohol is set on fire. After cooling, the glass is ready to be used for making wound prints. At in large numbers pus covering the wound, it is removed with sterile wet cotton swabs. After that, the surface of the glass, stepping back 1 cm from the narrow edge, is applied to the inflamed tissue. By moving the glass, several smears-imprints are successively applied. Tissue cells, exudate cells and microorganisms remain on the glass. When receiving smears, one should not pass the glass over the surface of the wound and thereby prevent the possibility of damage to the cellular elements of the exudate. In order not to distort the picture of the mutual arrangement of phagocytes and microorganisms, sometimes located in nests, you need to lightly touch the glass to the selected area of the wound and immediately take it away in a position strictly perpendicular to the wound surface. For completeness wound process it is better to make prints from different parts of the lesion, for example, from the center to the periphery.

The obtained wound smears-imprints are dried, then fixed for 5 minutes with methyl alcohol (ethyl alcohol in an equal mixture with ethyl ether for 15 minutes). Fixed and dried in a thermostat or in air, the preparations are stained according to the Romanovsky-Giemsa method.

When microscopy of stained smears-imprints pay attention to the presence of neutrophils of varying degrees of maturity, micro- and macrophages, phagocytic pathogens inflammatory process. Establish the activity of phagocytes in different parts of the wound.

According to the cytograms of wound prints, it is possible to determine the activity of protective and regenerative reactions of the body, the degree of bacterial contamination and pathogenicity of microorganisms that infect the wound. These factors determine the dynamics of wound healing. The detection of polymorphonuclear neutrophilic leukocytes, actively phagocytic pathogens of the infectious process, indicates a high activity of the phagocytic reaction. In the later period of wound healing, a good sign is the detection of a large number of macrophages - monocytic cells.

Registration of the protocol of experience. Write down the technique for preparing smears-imprints. The results of the cytological analysis of the test exudate are noted, discussed and conclusions are drawn.

Questions for knowledge control:

1. Inflammation. Concept definition. 2. Etiological factors causing inflammation. 3. External signs of inflammation and their characteristics. 4. Disorders of blood circulation and microcirculation in the area of inflammation. 5. Characteristics of metabolic disorders in the focus of inflammation. 6. Role biologically active substances in the pathogenesis of inflammation. 7. Classification of inflammations. 8. Types of exudate. 9. Views purulent inflammation. 10. Emigration of leukocytes during inflammation, the main theories explaining this phenomenon. 11. The doctrine of phagocytosis. Completed and incomplete phagocytosis. 12. Properties of exudate. 13. Classification of inflammation according to the predominance of alteration, exudation and proliferation. 14. Inflammation as a reaction of the whole organism to damage. 15. Pathogenesis of inflammation. Characterization of the stages of alteration, exudation and proliferation. 16. Outcomes of inflammation. 17. The biological role of inflammation. 18. Features of the course of inflammation in the main types of farm animals (horses, cattle, pigs and birds).