Clinical Laboratory Sections PDF

PMLS 1: Module 4 and Module 5 z The Clinical Laboratory Sections Instructor: Princess Jonalyn Agabao ([email protected])  Module 5: PMLS 1 Unit 3: z THE CLINICAL MICROSCOPY SECTION  z OBJECTIVES  Identify...

PMLS 1: Module 4 and Module 5 z The Clinical Laboratory Sections Instructor: Princess Jonalyn Agabao ([email protected])  Module 5: PMLS 1 Unit 3: z THE CLINICAL MICROSCOPY SECTION  z OBJECTIVES  Identify and differentiate the microscopic, chemical, and physical examination of urine; and  Enumerate historical events and figures that contributed to the development of routine urinalysis.  Clinical Microscopy  Involves the performance of scientific analysis on body fluids other than blood: Cerebrospinal Seminal Fluid Fluid Pleural Fluid  Clinical Microscopy  Involves the performance of scientific analysis on body fluids other than blood:  serous fluids a b  synovial fluid (a) c  amniotic fluid (b)  Urine (c) Urinalysis Chemical Physical Microscopic  The Clinical and Laboratory Standards Institute (CLSI) defines urinalysis as “the testing of urine with procedures commonly performed in an expeditious, reliable, accurate, safe, and cost-effective manner.” Main reasons for performing urinalysis include: 1. aiding in the diagnosis of disease, 2. screening asymptomatic populations for undetected disorders, and 3. monitoring the progress of disease and the effectiveness of therapy z BRIEF HISTORICAL BACKGROUND OF URINALYSIS Hippocrates (5th century)  Wrote a book in “uroscopy” Rufus of Ephesus (50 AD)  Made the first description of hematuria as the presence of blood in the urine Isaac Judaeus (900 AD)  Considered as one of the founders of the origins of nephrology  In his book Kitab al Baul (Book of Urine), detailed the concepts of urine formation, urinary sediments, and urine characteristics in relation to diseases. Middle Ages  Physicians concentrated their efforts very intensively on the art of uroscopy, receiving instruction in urine examination as part of their training  1140: Color charts had been developed that described the significance of 20 different colors Middle Ages  Chemical testing of urine involved “ant testing” and “taste testing” for glucose  “Pisse prophets”, charlatans without medical credentials, began offering health-related predictions of patients using their urine samples Thomas Bryant (1627)  Published a book that exposed the scam offered by the “pisse prophets”  Revelations uncovered in his book inspired the passing of the first medical licensure laws in England Jean Baptiste van Helmont  Introduced the gravimetric analysis of urine by weighing a number of 24-hour urine specimens. No significant conclusions were derived from his measurements Frederik Dekker (1694)  Discovered albuminuria by boiling urine; Observed that proteins in the urine precipitated when boiled with acetic acid Thomas Addis (1926)  First attempt to standardize the quantitation of formed elements in urine microscopic analysis  Addis count: used a hemocytometer to count the number of RBCs, WBCs, casts and epithelial cells present in a 12-hour urine sample Calculate Addis count RBCs Epithelial cells WBCs Hyaline and Granular casts Richard Bright (1827)  Introduced the concept of urinalysis as part of a doctor’s routine patient examination  Revealed the presence of albumin in heated urine samples  Studied renal diseases and clearly established the overall correlation of edema, albumin in urine, and diseased kidneys observed after death 1930s  Number and complexity of the tests performed in a urinalysis had reached a point of impracticality, and urinalysis began to disappear in routine examinations With the development of MODERN TESTING TECHNIQUES → routine urinalysis remained as an integral part of patient examination Reagent Strips (Urine Test Strip)  Rescued routine urinalysis by making chemical and physical examination of urine samples easier  1950s: Urine test strips were first made on industrial scale and offered commercially  1964: The company Boehringer Mannheim (today Roche) launched its first Combur test strips  z ROUTINE WORK IN THE CLINICAL MICROSCOPY SECTION  Accurate urinary results greatly depend on the quality of the specimen collected. With this in mind, laboratories routinely request patients to collect urine samples using the Midstream Clean- Catch Method Steps in midstream clean-catch method: a. Patients must be provided instructions for cleansing. Mild antiseptic towelettes are recommended as cleansing materials  Patients are instructed to wash their hands before beginning the collection Steps in midstream clean-catch method:  Male patients should clean the glans penis. For uncircumcised patients, they should withdraw the foreskin  Female patients should separate the labia and clean the urinary meatus and surrounding area b. After cleansing, patients are to void first into the toilet, then collect an adequate amount of urine in a sterile container, and finish voiding into the toilet Check the Sample: Name Date and Time collected 1st void/ 2nd Void  ROUTINE URINALYSIS a. Physical Examination of Urine Color Clarity  ROUTINE URINALYSIS a. Physical Examination of Urine Color  Normal urine color: straw, pale yellow, yellow, dark yellow, & amber (relatively dehydrated states)  Normal urine pigments responsible for coloration:  Urochrome: Responsible for the YELLOW color of urine  Uroerythrin: a PINK pigment most evident in REFRIGERATED SPECIMENS as a result of amorphous urates precipitation  Urobilin: Imparts an ORANGE-BROWN color to urine samples that are not fresh  ROUTINE URINALYSIS a. Physical Examination of Urine Color  ROUTINE URINALYSIS a. Physical Examination of Urine Color Clarity  Refers to the TRANSPARENCY / TURBIDITY of a urine specimen  Amount of turbidity will correspond to the amount of material observed during microscopic examination  To examine clarity, visually examine the specimen in a clear container while holding it in front of a light source.  Reporting:  Clear: No visible particulates, transparent  Hazy: Few particulates, print easily seen through urine  Cloudy: Many particulates, print blurred through urine  Turbid: Print cannot be seen through urine  Milky: May precipitate or be clotted Note: Non-pathologic cause of urine turbidity Pathologic cause of urine turbidity Specific Gravity  INDICATOR OF CONCENTRATION OF DISSOLVED MATERIAL IN THE URINE  Affected by both NUMBER AND SIZE of particles in the solution  Methods of measuring specific gravity:  Direct measurement using urinometers (hydrometer)  Indirect measurement using refractometer which measures refractive index of the urine sample REFRACTOMETER REFRACTOMETER Odor (Incidental characteristic/ observation)  Not part of routine urinalysis, only an incidental observation Chemical Examination of Urine  Chemical parameters (and specific gravity) of urine samples are routinely assessed using reagent strips (urine strips) Reagent Strips (Urine Strips)  Consist of chemical-impregnated absorbent pads attached to a plastic strip  A color-producing chemical reaction takes place when the absorbent pad comes in contact with urine  Reactions are interpreted by comparing the color produced on the pad with a chart supplied by the manufacturer Reagent Strips (Urine Strips) 1. Saturating chemical pads of dipstick Reagent Strips (Urine Strips) 2. Blotting edge of dipstick Reagent Strips (Urine Strips) 3. Comparing for color reactions using: a. Reaction Chart Reagent Strips (Urine Strips) 3. Comparing for color reactions using: b. Reaction Strip Reader 1.Leukocyte 2.Nitrite 3.Urobilinogen 4.Protein 5.pH 6.Blood 7.Specific Gravity 8.Ketone 9.Bilirubin 10.Glucose Microscopic Examination of Urine Preparation: 1. Centrifugation of urine sample 2. Decantation of supernatant liquid 3. Aspiration of 20 µL (some labs use one or two drops) of urine sediments and placement of the aspirated sample on top of a glass slide 4. A cover slip is then placed on top of the slide before microscopic observation Microscopic Examination of Urine Preparation: Microscopic Examination of Urine Preparation: Both the low power objective and the high power objectives are used in the microscopic examination Assessed elements:  Cellular elements: Red blood cells, white blood cells, epithelial cells (normal and pathologic variations)  Urinary crystals  Casts:  Only elements found in the urinary sediment that are unique to the kidney  Formed within the kidney (lumens of the distal convoluted tubule and collecting ducts)  Mucus threads  Bacteria  Other miscellaneous elements: Yeast cells, parasites, spermatozoa RBCs Mucus threads WBCs Hyaline casts Note: Normal Crystals in Urine MANNER OF REPORTING per LOW POWER FIELD: Epithelial cells: words Mucus threads: words Amorphous urates: words Casts: range (number) per HIGH POWER FIELD: WBC and RBC: range (number) Bacteria: words Yeast cells: words Crystals: words