Para Lab (Prelim) - Laboratory Diagnosis for Parasite Examination PDF

PARA LAB (PRELIM) LABORATORY DIAGNOSIS FOR Should be able to confirm a clinical impression that the condition has a PARASITE EXAMINATION parasitic nature...

PARA LAB (PRELIM) LABORATORY DIAGNOSIS FOR Should be able to confirm a clinical impression that the condition has a PARASITE EXAMINATION parasitic nature Aid a clinician in the choice of PARASITISM appropriate medication Parasites are organism that lives on or in Help in monitoring effect of a treatment a host organism and get its food from or at regimen the expense of its host Through gross examination (physical Parasitic INFECTION the state of being appearance, consistency), and infected; parasitism caused internal body microscopic examination problems (endoparasitic condition) Demonstration of parasites: Parasitic INFESTATION the state of being ◆ Definite diagnosis- looking for a invaded or overrun by parasites; parasite (egg/ova, larva, cyst, superficially (ectoparasitic condition) trophozoite) LIFE CYCLE ◆ Presumptive diagnosis Mode of transmission: (host-immune response)- useful Oral-fecal- mouth, anus when parasites are not Blood contact- thru improper blood demonstrable even with active letting techniques infection Sexual intercourse- humans secrete Detection of fluids antigen-antibody reaction: Vector-borne- thru organisms that Antibody- protective protein bring parasites (e.g mosquito) produced by the immune Infective stage: system in response to the Morphologic form presence of a foreign Diagnostic stage: substance Laboratory retrieval method Antigen- substance that is COMMON PARASITES capable of stimulating an Protozoa immune response, specifically Amoeba activating lymphocytes Ciliates FACTORS IN PERFORMING ACCURATE Sporozoa DIAGNOSIS Flagellates Proper specimen collection and Arthropods handling Ticks Proper processing of specimens Mites Skills of the laboratory examiner Helminthes Quality of equipment used Nematodes COMMON LABORATORY SPECIMENS FOR Cestodes PARASITIC INFECTION Trematodes Stool Tissue & blood dwelling nematodes Blood Filariae TYPES OF SAMPLES FOR PARASITE D. Medinensis INFECTION T. Spiralis Fecal/ stool specimen 2 TYPES OF DIAGNOSIS IN PARASITISM Most commonly examined when Clinical diagnosis- mostly doctors/nurses infection with intestinal parasites is do it suspected; for ova and parasite Signs (something I can detect) detection Symptoms (something only the patient It is important to have the whole knows) specimen submitted in order to make Laboratory diagnosis- only medtechs adequate gross and microscopic examinations PARA LAB (PRELIM) Blood specimen Duodenal aspirates are employed for 2nd specimen commonly examined in the demonstration of infections with G. the lab (for material parasites, filarial lamblia, S. stercoralis, F. buski, or worms, trypanosomes, leishmanial & Cryptosporidium toxoplasma infections); serum may be This specimen is collected by the use used for serologic tests of tubing (duodenal intubation) or Purged and Enema specimens by Entero-test method When routine examination of stool has liver & lung aspirates are employed been consistently negative yet there is for the deomnstration of E. histolytica. a strong clinical suspicion of intestinal Such materials should be examined in amoebiasis direct wet mount & on permanent Purgative solution stained slides ◆ Magnesium sulfate (epsom salts) Biopsy materials ◆ Sodium sulfate Biopsy of skin, superficial lymph ◆ Phosphosoda nodes, visceral organs like the liver & Enema is a technique used to other can be processed by routine stimulate stool evacuation histotechniques for demonstrating A liquid treatment most commonly parasitic stages used to relieve severe constipation. handled by pathologists only The process helps push waste out Corneal scrapings of the rectum when you cannot do Diagnosis of Acanthamoeba keratitis so on your own is best achieved by this specimen Urine/ genital specimen Non-nutrient agar plates (culbertson’s Urine is the specimen of choice for the medium) recovery of S. haematobium eggs, Calcoflour white stain/ histologic microfilarie of Wuchereria, specimen Onchocerca, Loa-loa & Brugia, & on Cerebrospinal fluid rare occasions Strongyloides larvae On rare occasion, CSF may be Urethral &vaginal discharge specimens infected with parasitic organisms & prostatic secretions are examined by (Naegleria, Acanthamoeba, direct wet mount for the presence of Toxoplasma & Trypanosoma) T. vaginalis Patients with these infections generally Sputum specimen exhibit symptoms of meningitis & a Useful in recovering trophozoites of E. lumbar puncture is performed histolyyica in cases of Mouth and nasal discharge pleuropulmonary amoebiasis & the For the recovery of E. gingivalis & T. free scolices of Echinococcus tenax that can cause parasitic infection granulosus in the event of rupture of of the oral mucosa & gingival (mouth pulmonary hydatid cyst discharge) This can also demonstrate eggs of P. Nasal discharge is collected and westermani, lung flukes & examined for the presence of occasionally, larvae of nematodes Naegleria fowleri (ascaris strongyloides, hookworms & others with hear-lung route) Aspirates STOOL SPECIMEN AND Specimens that has been drawn from the body by suction EXAMINATION Protoscopic aspirates and scrapings are used in confirming WHY STOOL? suspicion of amoebic ulcers in lower Diagnosis of parasite infections often sigmoid colon & rectum depends on observing parasite forms that include protozoa, ova, larva, or adult forms PARA LAB (PRELIM) Specimen types include stools, tissue, Labels and information: urine, sputum, and blood Patient’s full name 95% of parasite specimens are seen and Time & date collected diagnosed through stool specimen Request form Stool (poop or feces) Contamination: Normal part of the digestive process Urine Consists of waste products that are Water being eliminated from the body Diaper’s fibers It is the sample choice in parasite Residues of toilet papers recovery because the digestive tract Reject sample if: is the source and storage of body’s Unlabeled/ mislabeled nutrients Contaminated ◆ Parasites mostly reside at the GI Stool sample submitted passed 30 tract for nutrients, proliferation & minutes other biochemical processes Untightened container WHY IT’S DONE? TYPES OF PRESERVATION Patient is possibly having signs and Refrigeration: symptoms of parasitic infection Good for eggs, larvae & amoebic Diarrhea for an extended period of time cysts. Do not refrigerate if you Blood or mucus in the stool suspect amoebic trophozoites. Abdominal pain 10% formalin Nausea, headaches, fever Good for eggs, larvae, and amoebic Outbreak of parasitic illness cysts Drinking untreated water MIF (Merthiolate-Iodine-Formalin) Recently visited a developing country Concentration procedures as well IDEAL STOOL SAMPLE as presevative; good for eggs, larvae, Should be free of antimicrobial agents or and amoebic cysts other substances that inhibit parasite PVA (Polyvinyl Alcohol) growth. Barium from enemas can Best for amoebic trophozoites; can obscure parasites during microscopic prepare permanent stain slides from examination specimens preserved this way At least 3 grams/ 3 tablespoons on 3 SAF (Sodium Acetate- Acetic consecutive days acid-Formalin) Should be free of urine because urea and Good for amoebic trophozoites; acidic pH inhibit some parasites and distort environmentally safer than PVA their morphology and destroy motile Schaudinn’s fluid organisms Used for fresh stool samples; good for Antibiotics such as Tetracycline modify trophs and cysts intestinal flora and may prevent parasite COMPONENTS OF ROUTINE recovery for 2 weeks after drug cessation PARASITOLOGY Liquid stools best to detect trophozoites; Macroscopic/ gross examination formed stools best to detect ova & cysts Microscopic examination CONSIDERATION IN SAMPLE Chemical examination (gimention ra niya) COLLECTION MACROSCOPIC EXAMINATION Time frame: The specimens are screened and 30 mins- Liquid stools (trophozoites) examined for the presence of gross 1 hr- semiformed specimen (mixture of abnormalities trophozoites & cyst) Done with the help of the human eye 24 hrs- formed specimens (ova & Color and consistency parasites), place an aliquot in STOOL COLORS preservative and refrigerate the Brown remainder Healthy stool PARA LAB (PRELIM) There’s a big range that can be CONCENTRATION TECHNIQUES considered normal Formalin-ethyl acetate sedimentation Yellow Ethyl acetate removes fats and oils Foods can cause yellow stool but so Formalin preserves organisms can metabolic condition or liver Advantage: problems. See a doctor ◆ Can stay in formalin stage High fat diet, eating gluten products indefinitely, easy to perform, detects all parasites Green Disadvantage; Certain foods can turn your poop green ◆ More debris (leafy vegetables, purple-colored Zinc sulfate flotation technique foods), but so can metabolic issues, Specific gravity of zinc sulfate is like irritable bowel syndrome greater than ova, cysts, and larva so Stool of a baby they float on top of the zinc sulfate Red solution Colored foods can stain your poop Specific gravity of zinc sulfate should (cranberries, beets), but red stool can be 1.18 be a sign of bleeding Higher specific gravity allows the Bleeding in the lower GI tract eggs/ cysts to float on top of the White/clay solution Sign of obstruction. See a doctor right Flotation solution used must have away higher/ heavier specific gravity than Lack of bile, and bleeding in the most common parasite eggs/ cysts upper GI tract Advantage: Black ◆ Not flammable, produces a cleaner Some medication can stain stool black preparation (bismuth, iron supplements) Disadvantage: Bleeding in the upper GI tract ◆ Large eggs (schistomes) and STOOL CONSISTENCIES operculated eggs (D. latum) are Type 1 often missed Separate hard lumps Formalin ethyl acetate sedimentation Very constipated procedure Type 2 Formalin is added to the stool then mix Lumpy and sausage like Then add ether to separate the Slightly constipated formalin, debris and sediment Type 3 Sausage shape with cracks in the surface Normal Type 4 Smooth, soft sausage/ snake Normal Type 5 Soft blobs with clear-cut edges Lacking fibre Type 6 Mostly consistency with ragged edges Inflammation Zinc sulfate flotation technique Type 7 procedure Liquid consistency with no solid pieces Inflammation PARA LAB (PRELIM) protozoa. Low power is used to scan for large helminth eggs/ larvae. High power is used to detect and identify smaller parasites and larger helminth egss and larvae 5. Any parasites detected are reported out by their scientific name & quantity observed D’ ANTONI’S METHOD Iodine stains the cysts of amoebae and other protozoa, revealing some details that cannot be seen in the unstained preparation WET MOUNT AND Trophozoites are rapidly killed and are HAY INFUSION sometimes unidentifiable after iodine staining; the stain should not be applied DIRECT WET MOUNT until after the specimen has been Most useful for the detection of trophic thoroughly examined in the unstained form of amoebae and flagellates, condition allowing the observer to study the motility Gram’s iodine or Lugol’s solution gives of the organisms, which is often satisfactory results, but a modified D’ characteristic Antoni’s iodine solution is preferable Particularly appropriate for immediate The stain will diffuse and emphasize the examination of stool and for other fresh morphology of cysts, trophozoites, and specimen in which protozoal disease is eggs suspected Iodine will stain the organisms a dark Film should not be too thick orange brown color Convenient rule of thumb is to prepare Water will rupture some trophozoites, the film just thin enough so that ordinary rendering them unrecognizable newsprint can easily be read through it Procedure: Principle: 1. Place a drop of D’ Antoni’s iodine solution Collect sample from container on a slide Add sample to slide 2. Pick up a small amount of fecal material on Place cover slip on sample an applicator stick using the same criteria NSS - normal saline solution in the saline procedure for selection of the iodine stain - D’ Antoni’s method proper areas DIRECT FECAL SMEAR 3. Emulsify in the iodine solution and cover (THROUGH NSS) PROCEDURE with a coverslip 1. Place a drop of saline on the slide 4. Examine on low and high power as 2. Pick up a small amount of fecal material on described in the previous procedure the end of an applicator stick. IODINE SOLUTIONS a) NOTE: take small amounts of material Lugol’s solution from several different areas, especially Distilled water- 100 ml from bloody and/ or mucoid areas Potassium iodide- 10 g 3. Emulsify in the saline and cover with a Iodine crystals- 5 g coverslip. Examine on low and high power Gram’s iodine objectives Lugol’s solution- 1 part a) NOTE: a smear should be thin enough Distilled water- 14 parts so that a printed page can be read Modified D’ Antoni’s iodine through it Distilled water- 100 ml 4. The entire preparation must be examined Potassium iodide- 1 g for the presence of eggs, larvae, and Powdered iodine crystals- 1.5 g Saline smear (without iodine) PARA LAB (PRELIM) Presence of eggs, protozoal troph, and 4. Add about 2-3 tbsp of canal water. Cover motility half-closed and stand at room temperature Iodine smear for 2-3 days Cyst morphoogical details, presence 5. Using a dropper, draw sample from the and motility bottom of the bottle and place on drop on a SUGGESTED FREQUENCY clean glass slide and place coverslip DISTRIBUTION CHART 6. Examine under the microscope and DENSITY PROTOZOA HELMINTHS observe the motility of protozoa 2 to 5 2 to 5 organisms per organisms per rare 22 mm 22 mm square square coverslip coverslip 1 organism 1 egg/larva per 5 to 10 per 5 to 10 few high-power low-power fields (44x) fields (10x) 1 to2 1 to 2 organisms per eggs/larvae high-power per low-power field, to as field moderate few as 1 organism per 2 to 3 high-power fields Several Several eggs/ organisms in larvae in many every every high-power low-power field field HAY INFUSION For protozoa detection Most protozoa multiple by binary fission. Can come from four groups: amoebae, flagellates, cilliate, and sporozoans The most well known culturing technique Culture- artificially growing them outside their natural habitat BASIC PRINCIPLE OF HAY INFUSION Water is boiled and hay/grass is added Boiling breaks down the hay and serves as culture medium for the growth of bacteria These bacteria will serve as food for the protozoans found in the water that is added to the hay solution Procedure 1. Boil 1 glass of water 2. Add hay and simmer for 3 minutes 3. Transfer preparation into a clean bottle and allow to cool. Do not remove the hay