Content
The stool parasitological examination is an examination that allows the identification of intestinal parasites through the macro and microscopic evaluation of feces, in which cysts, eggs, trophozoites or adult parasitic structures are visualized, which helps the doctor to diagnose diseases caused by parasites such as hookworm, ascariasis, giardiasis or amebiasis, for example.
Thus, this examination is indicated by the doctor when the person shows signs and symptoms of worms such as abdominal pain, loss of appetite or weight without apparent cause, as this way it is possible to identify the cause of the alteration and to indicate the most appropriate treatment.
What is it for
The parasitological examination of feces serves to identify parasites responsible for gastrointestinal changes, and adult cysts, trophozoites, eggs or worms can be identified in the feces, the latter being rarer to be identified. Thus, when the person shows symptoms of parasitic diseases such as abdominal pain, loss of appetite or swollen belly, for example, the doctor may indicate that the stool exam is performed. Learn to identify the symptoms of worms.
The main parasites found in feces through parasitological examination are:
- Protozoa: these are simple parasites whose infection is usually identified through the presence of cysts in the stool, with cysts of Entamoeba histolytica, responsible for amebiasis, and Giardia lamblia, which is responsible for giardiasis.
- Helminths: they are more elongated parasites and whose infection is usually identified through the presence of a large quantity of eggs in the feces, with eggs of Ascaris lumbricoides, Taenia sp., Trichuris trichiura, Enterobius vermicularis and Ancylostoma duodenale.
When a large quantity of parasite eggs is identified in the feces, for example, the doctor usually indicates the performance of an image exam, such as colonoscopy or endoscopy, in order to identify whether there are adult worms in the digestive system, which is the case infection Taenia sp., Ascaris lumbricoides andAncylostoma duodenale.
In addition, it is common that in addition to the parasitological examination of feces, the doctor indicates the performance of co-culture, especially if the person has diarrheal or more pasty stools, as it can also be indicated for infection by bacteria, with co-culture being the most indicated test in this case. Understand what coproculture is and what it is for.
Ascaris lumbricoides egg
How is done
The stool parasitology is made from the analysis of a stool sample that must be collected by the person and taken to the laboratory within 2 days after collection for the analysis to be carried out. The recommendation is that 3 samples be collected on alternate days, because some parasites have variations in their life cycle, and structures cannot be observed if the samples are collected on consecutive days.
In addition, it is important that the sample collected has not had contact with urine or the vessel and, in the event of the presence of mucus or a whitish spot in the stool, it is recommended that this area be collected for analysis. It is also recommended that you have not used laxatives, antidiarrheal drugs or antibiotics at least 1 week before the collection period, as they may interfere with the result. See more about stool examination.
In the laboratory, the stool is evaluated macroscopically, that is, the appearance and color of the stool is evaluated, which is important for the best diagnostic technique to be performed for the examination, since according to the characteristics of the stools, hypotheses of the stool may arise. type and degree of infection, which allows more appropriate techniques to identify adult cysts, eggs, trophozoites or worms.
Then, the samples go through a preparation process so that they can be evaluated microscopically and, thus, it is possible to carry out the research and identification of parasitic structures, which is indicated in the report. The report indicates the diagnostic method performed, whether parasitic structures were observed and identified, the structure and species of the parasite, and this information is important for the doctor to indicate the most appropriate treatment.
Check out more details on how to collect the stool exam in the following video: