Concentration Method in Parasitology
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What is the primary purpose of concentration methods in parasitology?

  • To observe detailed features of protozoa by staining intracellular organelles
  • To identify helminth eggs and larvae
  • To detect small numbers of parasites that might not be detected using direct preparations (correct)
  • To remove all debris from the sample

    • What is the principle of the Formalin-Ethyl Acetate Sedimentation Procedure?

  • Parasites are heavier than the solution (correct)
  • Parasites are less dense than the solution
  • Parasites float to the surface during centrifugation
  • Fecal matter is heavier than the solution

    • What type of sample is typically used for staining in concentration methods?

  • PVA preserved sample (correct)
  • Fresh stool specimen
  • Formalin fixed sample
  • SAF fixed sample

    • What is the main advantage of Trichrome stain?

    <p>It has a long shelf life and easy procedure</p> Signup and view all the answers

    What is the advantage of using concentration methods over direct preparations?

    <p>It enables the detection of small numbers of parasites</p> Signup and view all the answers

    Which of the following parasites can be detected using concentration methods?

    <p>Protozoan cysts, oocysts, helminth eggs, and larvae</p> Signup and view all the answers

    What is the purpose of reviewing 300 fields in sediment techniques?

    <p>To ensure the slide is considered negative</p> Signup and view all the answers

    What is the main difference between sedimentation and flotation techniques?

    <p>In sedimentation, parasites are heavier than the solution, while in flotation, they are less dense</p> Signup and view all the answers

    What is the purpose of centrifugation in concentration methods?

    <p>To separate parasites from fecal debris</p> Signup and view all the answers

    What is the limitation of using SAF fixed specimens for staining?

    <p>Staining is limited to iron-hematoxylin only</p> Signup and view all the answers

    What is the purpose of using a commercial antibody in stool screening methods?

    <p>To detect antigen in the patient's specimen</p> Signup and view all the answers

    What type of parasites are detected using Acid fast stain?

    <p>Oocysts of Cryptosporidium, Isospora, and Cyclospora</p> Signup and view all the answers

    What is the advantage of preparing slides from fresh stool specimens?

    <p>It allows for the immediate fixation of the sample</p> Signup and view all the answers

    What is the purpose of sealing the slides with a permanent mounting sealant after staining?

    <p>To preserve the slides for future reference</p> Signup and view all the answers

    What is the advantage of Iron hematoxylin stain?

    <p>It reveals excellent morphology of the intestinal protozoa</p> Signup and view all the answers

    What is the purpose of centrifugation in sedimentation techniques?

    <p>To concentrate the parasites in the sediment of the tube</p> Signup and view all the answers

    What is a potential health risk associated with PVA preserved specimens?

    <p>Exposure to mercuric chloride</p> Signup and view all the answers

    What is a characteristic of stool that may suggest the presence of protozoan trophozoite?

    <p>Soft or liquid stool</p> Signup and view all the answers

    What is the main advantage of using Sodium Acetate Formalin (SAF) over PVA?

    <p>SAF is free of formalin and mercury</p> Signup and view all the answers

    What is the primary purpose of macroscopic analysis of stool?

    <p>To examine the stool for gross abnormalities</p> Signup and view all the answers

    What is the significance of stool consistency in parasite detection?

    <p>Stool consistency serves as an indication of potential parasite presence</p> Signup and view all the answers

    What is the main advantage of the Alternative Single-Vial System?

    <p>It is free of formalin and mercury</p> Signup and view all the answers

    What is the purpose of microscopic analysis of stool?

    <p>To detect the presence of parasites in stool</p> Signup and view all the answers

    What is a characteristic of formed stool?

    <p>It is hard or formed</p> Signup and view all the answers

    What is the significance of the color of stool in parasite detection?

    <p>It indicates the patient's condition or status</p> Signup and view all the answers

    What is a disadvantage of PVA preserved specimens?

    <p>Difficult disposal of the specimens</p> Signup and view all the answers

    What is the purpose of the modified trichrome stain in parasitic infections?

    <p>To detect spores of microsporidia</p> Signup and view all the answers

    What is the primary advantage of antigen detection methods?

    <p>They are highly sensitive and specific for certain parasites</p> Signup and view all the answers

    What is the limitation of examining stool specimens in parasitic infections?

    <p>It may not detect the infectious agent in certain parasitic infections</p> Signup and view all the answers

    What is the purpose of using other intestinal specimens in parasitic infections?

    <p>To detect parasites that are not present in stool specimens</p> Signup and view all the answers

    What is the characteristic of rapid test or stool screening methods?

    <p>They are highly sensitive and specific</p> Signup and view all the answers

    Which of the following is NOT an assay method for detecting parasitic infections?

    <p>Polymerase Chain Reaction</p> Signup and view all the answers

    What type of parasites can be isolated with culture?

    <p>E. histolytica, T. vaginalis, Leishmania spp.</p> Signup and view all the answers

    What is the primary advantage of antigen detection over antibody detection?

    <p>It is more reliable and indicative of current infection.</p> Signup and view all the answers

    What type of laboratories offer immunologic testing?

    <p>Specialized laboratories and research facilities.</p> Signup and view all the answers

    What information should be included in the report of a positive specimen?

    <p>The scientific name and stage of the parasite.</p> Signup and view all the answers

    How should the presence of blood cells be reported in a specimen?

    <p>Semi-quantitatively, as rare, few, moderate, or many.</p> Signup and view all the answers

    What is the primary reason why immunologic testing is not usually performed in routine laboratories?

    <p>The tests require specialized expertise.</p> Signup and view all the answers

    Study Notes

    Concentration Method

    • A microscope slide with a fixed sample that has been allowed to dry and subsequently stained is used to detect small numbers of parasites that might not be detected using direct preparations.
    • The purpose of concentration is to aggregate the parasites present into a small volume of sample and remove as much debris as possible.
    • Concentration techniques can be performed on fresh or preserved specimens and enable the detection of protozoan cyst, oocyst, helminth eggs, and larvae.

    Advantages and Disadvantages

    • Advantages: enables detection of small numbers of parasites, allows for detailed observation of protozoa by staining intracellular organelles, and is a viable alternative to the use of PVA and Schaundinn fixative.
    • Disadvantages: PVA that contains Schaundinn solution contains mercuric chloride, which can lead to potential health problems, and the disposal of such fixatives can be difficult.

    Single-Vial System

    • An alternative to PVA and Schaundinn fixative that is free of formalin and mercury.
    • Can be used for concentration techniques and permanent stained smears.
    • Some products can be used for performing fecal immunoassay.

    Clinical Parasitology Laboratory

    • MACROSCOPIC ANALYSIS: determines the color and consistency of the stool submitted, which may indicate the presence of parasites.
    • MICROSCOPIC ANALYSIS: detects the presence of parasites in stool specimens and involves three distinct procedures: sedimentation, flotation, and staining techniques.

    Stains

    • TRICHROME STAIN (Wheatley Trichrome): a widely used permanent stain with a long shelf life and easy procedure.
    • IRON HEMATOXYLIN: considered time-consuming, but reveals excellent morphology of intestinal protozoa.
    • SPECIALIZED STAINS: Acid-fast stain (detection of oocysts of Cryptosporidium, Isospora, and Cyclospora), Modified iron hematoxylin (detection of acid-fast parasites), and Modified trichrome stain (detection of spores of microsporidia).

    Stool Screening Methods

    • Alternative tests for detection of parasitic infection that use monoclonal antibodies to detect antigen in patient specimens.
    • Examples of rapid tests: Enzyme Immunoassay, Direct Fluorescent Antibody, and Membrane Flow Cartridge Antibody.

    Other Specimens and Laboratory Techniques

    • Examination of stool specimens may not detect parasites in some cases.
    • Additional procedures, such as culture, can be performed to reveal the presence of specific parasites.

    Immunologic Testing

    • Includes methods for antigen and antibody detection.
    • Antigen detection is more reliable, and a positive test result indicates current infection.
    • Antibody detection is more complex and must be interpreted cautiously.

    Reporting of Results

    • A positive specimen report should state the scientific name (genus and species), along with the stage that is present (e.g., cyst, trophozoite, larvae, eggs, adults).
    • Presence of blood cells should be reported semi-quantitatively (rare, few, moderate, many).
    • Fecal immunoassays should indicate the presence of antigens.

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    Clinical Parasitology Laboratory Procedures - Specimen Collection & Handling - PDF

    Description

    This quiz covers the concentration method used in parasitology to detect small numbers of parasites. It explains the process of preparing a microscope slide and staining to observe detailed morphology of protozoa cysts and trophozoites.

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