LABORATORY TECHNIQUES FOR MEDICAL PARASITOLOGY

THIS TOPIC IS FOR MEDICAL PARASITOLOGY

1. Unit 4: Laboratory techniques 4.1 The procedure for clinical specimen collection for parasitic investigations (stool, urine, blood, sputum, exdudates , swabs and aspirates).

2. Stool: 1. Preparation: Clean Container:  Use a clean, dry container or plastic wrap (like cling film) stretched over the toilet rim to catch the stool Avoid Contamination:  Ensure the stool does not come into contact with urine, toilet water, or any other foreign material.  No Special Preparation:  Generally, no special preparation is needed before collecting the sample

3. 2. Collection: Collect the Sample:  Pass the stool directly into the container or onto the plastic wrap, Transfer to Container:  Use a provided spoon or other clean implement to transfer the stool to the sterile container Adequate Amount:  For solid stool, 2 heaping spoonfuls are typically required, while for liquid stool, 4 spoonfuls (or at least 10 grams) are needed

4. 3. Handling the Specimen: Label:  Clearly label the container with your name, date, and time of collection.  Immediate Transport:  Transport the sample to the lab within two hours of collection, Refrigeration:  If the sample cannot be taken to the lab within two hours, it should be refrigerated. 

5. Urine: Types of urine specimens: 1. Random sample: Sample which is collected anytime during the day. Usually used only for routine screening because the composition of urine changes throughout the day. 2. First voided specimen: Sample also referred to as a first morning specimen. This sample is collected the first time the patient urinates in the morning. A first voided specimen is the most concentrated and is the preferred specimen for pregnancy testing, bacterial cultures and microscopic examinations. 3. Timed specimens: These specimens are used when the physician requires urine samples to be taken at specific intervals during the day. Twenty-four (24) hour urine specimens are required for creatinine clearance tests and many other hormone studies.

6. 4. Clean-catch midstream specimen: This sample type is collected if the urine is going to be cultured and examined for bacterial growth or used for cytology. 5. “Dirty collection:” This specimen will be used for DNA testing and the FIRST part of the voided stream is collected. 6. Catheterized specimen: These specimens are obtained by inserting a catheter or sterile flexible tube into the bladder via the urethra to withdraw urine. This procedure is done only by specially trained personnel

7. PROCEDURE Specimen collection: 1. Routine or random sample: The patient is given a non-sterile collection container and instructed to collect a midstream specimen in the container. This type of specimen is routinely used for urinalysis and may not be used for a culture and sensitivity. 2. First voided specimen: The patient is given a urine container to take home and instructed to collect a sample of the urine the first time he or she urinates in the morning. Because urine is not stable, the specimen should be returned to the laboratory within one (1) hour of collection. If that is not possible, the specimen should be refrigerated until it can be tested.

8. 3. Timed specimen: Timed specimens are usually a 24 hour urine collection. A. The patient is given a large container (approximately 1 gallon) that is labeled with the patient’s name and date. Space is provided to write the time the collection begins and ends. B. Before issuing the 24 hour urine container the type of testing ordered is checked for preservative requirements. This information can be found in the BVH( Blanchard Valley Hospital), Laboratory specimen collection manual and any required preservatives addition is done by a tech. Cautionary labels are also often applied to caution patients that the added preservative may be caustic. 24 hour urine specimens are also usually required to be refrigerated during the collection period. This information should be recorded on the label applied to the 24 hour container.

9. C. The test usually begins in the morning. The patient is told to empty their bladder and discard the urine in the toilet and record the time on the label of the urine container. For the next 24 hours, all urine must be collected in the container. The next day at the same time the test began the patient empties their bladder, collects the urine in the container, and records the time the test ended. The patient should be instructed to avoid fecal contamination of the specimen. D. The 24 hour urine specimen is brought to the laboratory as soon as possible as the 24- hour period is over.

10. 4. Clean-catch mid-stream specimen: Patients with orders for a urine culture and sensitivity are given the proper mid-stream urine collection kit and the appropriate instruction sheet. A. Give the patient a sterile urine collection kit. The kits are located in the out-patient lab. B. Explain to the patient that an instruction sheet is included in the kit. There are two sets of instructions. There are different instructions for males and females. Verify that the patient understands the instructions.

11. C. Male urine culture collection instructions: These are general instructions. BVH periodically changes the company which provides the mid-stream collection kits. Each manufacturer provides very specific instructions to correlate with their specific type of container. These instructions may vary slightly with different manufacturers. The current use kit instructions are the instructions provided to the patient.

12. 1. Wash hands thoroughly with soap and water, rinse and dry. 2. Open the collection package but DO NOT TOUCH INSIDE OF CUP OR RIM. Open the package of 3 towelettes (a disposable cloth treated with a  cleansing  agent, typically supplied in an individual sealed package, for  wiping  things clean.) . Retract foreskin if present. With the first towelette , cleanse the urinary opening of the penis starting at the center and work outward. Repeat the cleansing in the same manner with the two remaining towelletes . 3. Remove lid carefully from the collection container, DO NOT TOUCH the inside of the container or rim. Gently grasp the container.

13. 4. Begin to void urine, letting the first 20-25 ml pass into the toilet. Position the cup in the stream of urine until the container is about half to two-thirds full. Finish voiding into the toilet. 5. After obtaining the urine specimen, screw the lid on tightly again being careful to avoid touching inside the container or lid. 6. Bring the specimen to the lab within 1 hour or collection or store refrigerated for up to 24 hours.

14. D. Female urine culture collection instructions: These are general instructions. BVH periodically changes the company which provides the mid-stream collection kits. Each manufacturer provides very specific instructions to correlate with their specific type of container. These instructions may vary slightly with different manufacturers. The instructions included in the kit currently in use are the instructions provided to the patient 1. Wash hands thoroughly with soap and water, rinse and dry.

15. 2. Open the collection package but DO NOT TOUCH INSIDE OF CUP OR RIM. Open the package of 3 towelettes . While seated on the toilet spread labia major (outer folds). With the first towellete , wipe one side of the labia minora (inner fold) using a single downward stroke. Discard towellete . With the second towellete repeat the procedure on opposite side using a single downward stroke. Discard towellete . With the third towelette , cleanse meatus (center area) with a single downward stroke. Discard towellette . 3. Remove lid carefully from the collection container, DO NOT TOUCH the inside of the container or rim. Gently grasp the container. 4. Begin to void urine, letting the first 20-25 ml pass into the toilet. Position the cup in the stream of urine until the container is about one-half to two-thirds full. Finish voiding into the toilet.

16. 5. After obtaining the urine specimen, screw the lid on tightly again being careful to avoid touching inside the container or lid. 6. Bring the specimen to the lab within 1 hour of collection or store refrigerated for up to 24 hours. 5. “Dirty” specimen: The patient is given a sterile urine cup and told to clean as stated above for a clean-catch specimen. They are then instructed to collect the FIRST part of the voided stream. Fill the container one half to two thirds full and finish voiding into the toilet. Apply the cap tightly and label the cup. 6. Catheterized specimen: These specimens are collected by specially trained personnel only. All urine specimens should be promptly returned to the laboratory. Specimens must be labeled with the patient’s name, DOB, date, time of collection and ordering physician.

17. Blood: Venipuncture (Most Common Method): MATERIALS 1. Safety Needles, 22g or less 2. Butterfly needles. 21g or less 3. Syringes 4. Vacutainer tube holder 5. Transfer Device 6. Blood Collection Tubes. The vacuum tubes are designed to draw a predetermined volume of blood. Tubes with different additives are used for collecting blood specimens for specific types of tests. The color of cap is used to identify these additives. 7. Tourniquets. Single use, disposable, latex-free tourniquets 8. Antiseptic. Individually packaged 70% isopropyl alcohol wipes. 9. 2×2 Gauze 10. Sharps Disposal Container. An OSHA acceptable, puncture proof container marked “ Biohazardous ”. 11. Bandages or tape

18. 1. Preparation: The phlebotomist washes their hands, puts on gloves, and identifies the patient. They then select a suitable vein, typically in the antecubital fossa (inside the elbow) or back of the hand.  2. Vein Anchoring: The phlebotomist anchors the vein by holding the patient's arm and applying a thumb below the venipuncture site.  3. Tourniquet Application: A tourniquet is applied to make the veins more prominent and easier to access.  4. Needle Insertion: The phlebotomist inserts the needle into the vein at a 30-degree angle or less, swiftly and smoothly. 

19. 5. Blood Collection: The blood is drawn into a collection tube or syringe.  6. Tourniquet Removal: Once sufficient blood has been collected, the tourniquet is released before the needle is withdrawn.  7. Needle Withdrawal and Pressure: The needle is gently withdrawn, and pressure is applied to the site with a clean gauze or cotton-wool ball.  8. Post-Procedure: The patient is advised to hold pressure on the site for at least two minutes, avoid bending the arm, and to report any unusual symptoms. 

20. Capillary Blood Collection: 1. Preparation: The phlebotomist washes their hands, puts on gloves, and identifies the patient.  2. Skin Puncture: A lancet is used to puncture the skin, usually on a finger or heel, to collect a small amount of capillary blood.  3. Blood Collection: The blood is collected on a special strip of paper or into a small collection tube. 

21. Sputum: Sputum sample collection involves coughing up mucus from the lungs into a sterile container for lab analysis. The preferred time for collection is early morning, before eating or drinking. The sample should be a "deep cough" sample, thick and containing cells and mucous, not saliva. 

22. Step-by-step guide to collecting a sputum sample: Preparation:  Wash your hands thoroughly and rinse your mouth with water. Do not use mouthwash or brush your teeth immediately before collecting the sample. If you wear dentures, remove them.  Breathing Techniques:  Take three deep breaths, holding each breath for 5 seconds. Exhale slowly.  Deep Cough:  Cough deeply, focusing on bringing up mucus from deep within your lungs. Saliva is not acceptable; you need thick mucus.  Collecting the Sputum:  Open the sterile container provided and cough the sputum into it, ensuring you don't touch the inside of the container or lid with your hands. 

23. Sample Size:  Aim for at least 5-10 ml (1-2 teaspoons) of sputum.  Closure:  Screw the lid on the container tightly to prevent leaks.  Labeling:  Clearly label the container with your name, date of birth, and the date and time of collection.  Storage and Transport:  Place the container in a specimen bag and refrigerate it until it can be taken to the laboratory. The sample should be taken to the lab as soon as possible.  Multiple Samples:  If you are asked to collect multiple samples (e.g., for TB testing), follow the instructions for each day separately. 

24. Exdudates : To properly collect exudate samples for analysis, the most reliable method is to aspirate the fluid using a sterile needle and syringe.  If aspiration isn't feasible, swabs moistened with sterile saline can be used, but are generally less preferred.  The sample should be placed in an appropriate transport tube or vial, often an anaerobic transport tube, and transported to the lab as quickly as possible. 

25. 1. Choosing the Right Method: Aspiration: This is the preferred method, especially for abscesses or deeper lesions. It involves using a sterile needle and syringe to draw out the exudate directly from the source.  Swabs: If aspiration isn't possible, swabs moistened with sterile saline can be used to collect the exudate . However, it's important to use two swabs and gently roll them over the surface of the wound, focusing on areas with pus or inflammation. Swabs are generally not recommended for anaerobic cultures due to the potential for insufficient sample volume. 

26. 2. Proper Collection Technique: Aspiration: Remove surface exudate by wiping with sterile saline or 70% alcohol. Aspirate the deepest portion of the lesion or exudate with a syringe and needle. Inject the aspirated fluid into a sterile transport tube or vial.  Swabs: Moisten two sterile swabs with sterile, non- bacteriostatic saline. Gently roll the swab over the surface of the wound, focusing on areas with pus or inflamed tissue. Return the swab to the transport tube. 

27. 3. Transport and Preservation: Anaerobic Transport: For suspected anaerobic infections, use anaerobic transport tubes or vials.  Other Transport Media: For other infections, use sterile tubes or vials without preservatives.  Rapid Transport: Transport the sample to the laboratory as quickly as possible, ideally within a few hours.  Temperature: If the transport time is longer than a few hours, transport the sample on ice. 

28. 4. Documentation: Labeling:  Clearly label the transport tube with the patient's name, date of birth, date and time of collection, and the body site from which the sample was taken. Requisition Form:  Complete the requisition form with all necessary information.  5. Specimen Type: Pus/ Exudate : The preferred sample for bacterial, fungal, or mycobacterial cultures is pus or exudate . Tissue: For abscesses, a portion of the abscess wall should also be included in the sample. 

29. Swabs: A proper swab collection procedure involves explaining the process to the patient, ensuring hand hygiene and donning gloves, using a sterile swab to collect a sample from the targeted area, and properly labeling and handling the collected specimen Explain the Procedure:  Clearly explain the reason for the swab and the steps involved to the patient. Hand Hygiene:  Wash hands thoroughly with soap and water, or use an alcohol-based hand sanitizer. Don Gloves:  Wear sterile gloves to maintain hygiene and prevent contamination.

30. Swab the Area: For skin wound/ulcer swabs, roll the cotton tip across the wound, avoiding the perimeter. If the wound has a crust, remove it with a sterile needle before swabbing. If discharge is localized, swab from the clean area to the affected area to avoid cross-infection. Label the Swab:  Label the swab with relevant patient information, including the anatomical site of the swab.

31. Specimen Handling: Do not refrigerate the swab, as it can kill certain organisms. Discard used gloves and the swab in a biohazard waste bin. Clean the Area:  Clean the area where the swab was collected. Wash Hands:  Wash hands thoroughly after completing the procedure. 

32. Aspirates: Aspirate sample collection involves using a suction device (like a catheter connected to a suction pump) to withdraw fluids or tissues from the body for testing or diagnosis. The specific procedure varies depending on the area being aspirated, but generally involves inserting a catheter into the desired area and applying suction to collect the sample. 

33. Steps for Aspirate Sample Collection: Prepare the area:  Clean the area to be aspirated with an antiseptic solution.  Position the patient:  Ensure the patient is in a comfortable and stable position for the procedure.  Insert the catheter:  Carefully insert the catheter into the designated area, using a gentle and controlled movement.  Apply suction:  Activate the suction device to withdraw the sample.  Remove the catheter:  Once the desired sample is obtained, slowly withdraw the catheter.  Seal the sample:  Seal the container or tube containing the sample to prevent contamination.  Label and transport:  Properly label the sample and transport it to the laboratory for analysis as per established guidelines. 

34. Examples of Aspirate Sample Collection: Nasopharyngeal Aspirate: A sample is collected from the back of the nose and throat to test for respiratory infections like COVID-19 or influenza.  Tracheal Aspirate: A sample is collected from the trachea (windpipe) to test for respiratory infections or other lung conditions.  Fine Needle Aspiration (FNA): A thin needle is used to collect a sample of cells or tissue from a suspicious lump or mass, often for cancer diagnosis.  Gastric Aspirate: A sample is collected from the stomach to test for conditions like tuberculosis.