Laboratory Diagnosis of Parasitic Infections

Identifying parasites, especially protozoa, can be challenging, often requiring microscopic examination, which is time-consuming and labor-intensive. Sometimes a parasite isn't detected even if one is present.

Gathering information about a patient (history, symptoms, physical exam), doing lab tests, imaging (X-rays), and possibly surgery are all steps in diagnosing a parasitic infection.

Feces samples are collected in clean containers. Prevent contamination with urine, soap, or disinfectants, especially with samples for amoeba or protozoa. Fresh samples are best, but preserve samples as soon as possible if fresh isn't possible. Avoid medication for 3 days before testing.

Examining stool samples involves looking for abnormalities in color, consistency (formed/soft), and the presence of mucus or blood, which might indicate a parasite infection. Look for adult parasites and segments.

A preliminary diagnosis based on gathering patient history, taking a look at the patient and doing a preliminary lab test.

More tests, such as imaging and further lab analysis, or invasive surgery are required to arrive at definitive diagnosis, moving from a presumptive diagnosis to a definite one.

Avoid taking antacids, antibiotics, antiparasitics, barium, enemas, kaolin products, and oily laxatives three days before stool sample collection to avoid interfering with the test results.

A quick screening test for trophozoite motility, using fecal material or concentrated specimens.

A microscopic examination method for detecting motile trophozoites, larvae, and ova/cysts in a stool sample.

A method to differentiate protozoa (like amoebae) from other cells by staining nuclei with methylene blue and/or eosin.

Method to recover various eggs and cysts in stool samples via settling or centrifugation; removing debris by filtration and fixation.

Using a microscope to observe stool samples, identify parasites, distinguish elements (e.g. cysts, trophozoites).

Methods used to increase the concentration of parasitic organisms in stool samples, prior to examination.

Methods for making a fixed slide of the sample to preserve morphology of the parasites for microscopic examination.

A solution used in the flotation method for stool examination to separate parasites from debris.

A stool examination method that separates parasites from stool by sedimentation and allows examination of the concentrated material.

A technique used to separate parasites from fecal material by exploiting their differing densities.

The process of isolating parasites from stool samples using various techniques.

A method of preparing stool samples for microscopic examination involving staining, providing better visual identification.

A method for counting helminth eggs in stool samples, useful for epidemiological studies.

The process of analyzing stool samples to detect the presence of parasites, helminths, or other pathogens.

A method for recovering nematode larvae from stool samples based on their active movement in water.

A stool examination technique that uses centrifugal force to separate parasites based on different densities.

A stool examination technique using sugar solution to separate parasites based on density differences.

A method to cultivate nematode larvae, typically using filter paper, for identifying parasites like Strongyloides stercoralis and hookworms.

Methods used to detect infections using antibodies rather than the actual pathogen itself.

Identifying the presence of specific antigens (molecules) from a pathogen in a sample to detect a specific infection.

Identifying the presence of antibodies produced by the body in response to a pathogen, indicating a past or active infection.

A lab test that measures how well antibodies stop red blood cells from clumping together when exposed to a particular pathogen.

A lab test used to detect specific antigens in a sample by observing clumping of latex particles coated with antibodies

Enzyme-linked immunosorbent assay; a sensitive and specific test to measure antibodies or antigens in a sample.

Techniques, like DNA probes and PCR, used to directly identify and detect parasites in samples, without relying on the immune system.

Short, labeled pieces of DNA used to find specific DNA sequences in a sample.

Polymerase Chain Reaction: Lab technique that copies specific DNA sequences, used to detect small presence of parasites.

Techniques that identify and detect parasites by studying their DNA.