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Introduction of Clinical Laboratory Science


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Laboratory is a place that is equipped with different instruments, equipments and chemicals (reagents) etc., for performing experimental works, research activities and investigative procedures.

Medical laboratory is one part of the laboratory that is equipped with various biomedical instruments, equipments, materials and reagents (chemicals) for performing different laboratory investigative activities by using biological specimens (whole blood, serum, plasma, urine, stool, etc).

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Introduction of Clinical Laboratory Science

  2. 2. A – A good student is liked by teacher G – Greets everyone with smile O – Obedient O – On time for college D – Dresses neatly S – Studies with interest T – Treats everyone with smile U – Understands everything D – Does daily home work E – Eager to know new things N – Never misbehaves T – Talks little in class
  3. 3. Introduction Laboratory is a place that is equipped with different instruments, equipments and chemicals (reagents) etc., for performing experimental works, research activities and investigative procedures. Medical laboratory is one part of the laboratory that is equipped with various biomedical instruments, equipments, materials and reagents (chemicals) for performing different laboratory investigative activities by using biological specimens (whole blood, serum, plasma, urine, stool, etc).
  4. 4. Medical laboratory science Medical laboratory science is a complex field embracing a number of different disciplines such as: Microbiology, Hematology, Clinical Chemistry, Urinalysis, Immunology, Serology, Histopathology, Immunohematology and Molecular biology and others.
  5. 5. Contd… Immunology, Serology, Histopathology, Immunohematology and Molecular biology and others.
  6. 6. Medical Laboratory Technology The practice of modern medicine would be impossible without the tests performed in the clinical laboratory.  A medical team of pathologists, specialists, scientists, technologists, and technicians work together to determine the presence, extent, or absence of disease and provide data needed to evaluate the effectiveness of treatment.
  7. 7. Clinical or Medical Laboratory Laboratories that perform chemical and microscopic tests on: blood other body fluids tissues
  8. 8. Clinical Laboratories  Play a major role in patient care  Variety of settings  Two types of Clinical.Laboratory  Hospital lab.  Non hospital lab.  POLs  Reference laboratories(LABCORP/QUEST D.)  Government laboratories - federal  Center for Disease control and Prevention(CDC)  Epidemiology labs  Laboratory Response Network
  9. 9.  Government Laboratories- state  Premarital blood testing  PKU testing in newborns  Fungi,virus, and mycobacteria culture
  10. 10. Regulations of Clinical Laboratory  All laboratories, but research labs.are regulated by Federal and State agencies  CLIA’88- Clinical Laboratory Improvement Amendments of 1988: Is a revision to the original CLIA of 1967, specifies the minimum performance standards for all Clinical Laboratories
  11. 11. Objectives of CLIA’88  To ensure quality Laboratory Testing, amendments are continually revised, updated, clarified and refined  CMS:Center for Medicare and Medicaid Services,agency within the Department of Health and Human Services responsible for implementing CLIA’88
  12. 12. CMS  Any Laboratory performing Lab. tests in humans ,except for research Labs. Must obtain a certificate from CMS (center for medicare-medicaid services) to be allowed to operate
  13. 13. Laboratory Personnel  Director of the Lab.- Pathologist, MD, DO, or hold a doctorate in a related clinical field. Hold certification and have supervisory and clinical laboratory experience  Technical supervisor/Lab.Manager-someone educated in the clinical laboratory sciences who has additional business experience
  14. 14. Laboratory personnel  General supervisor for each area  Testing personnel:  Medical Technologists(MT/CLS)  Medical Lab.Technicians(MLT/CLT)  Medical assistants/nursing staff(POLs)
  15. 15. Departments of the Clinical Laboratory  Clinical Chemistry  Hematology  Microbiology  Blood Bank  Supports Services (Phlebotomy/Specimen Processing)
  16. 16. Clinical Chemistry  Tests perform in serum, plasma, urine and other body fluids such as spinal fluid, or joint fluid  Largest department in the Lab.  Toxicology  Special chemistry
  17. 17. Hematology  Studying of the cellular components of the blood  Quantitative or Qualitative  Coagulation  Urinalysis  Special hematology
  18. 18. Microbiology  Culture/identification microorganisms  From sputum, wounds, blood, urine and other body fluids  Inoculated in culture media  Organisms are identified and susceptibility test are performed  Bacteriology, virology, serology, parasitology
  19. 19. Blood Bank  Also called immunohematology or transfusion services  ABO group and Rh typing  Antibody testing  Storage of packed cells units  Processing of some components like platelets and cryoprecipitate
  20. 20. Support Services  Phlebotomists  Accessioning
  21. 21. POCT  Point of care testing brings the laboratory to the patient, also called bed-side testing  Use small simple analyzers  Portable instruments  Hgb, glucose, electrolytes,and cholesterol
  22. 22. Quality Assessment System  incorporated to each department’s procedure manuals and day to day operation  Standardized material are analyzed on each instrument to document precision, and reproducibility  Calibration, maintenance and repair of the instruments is recorded  Participate in proficiency testing programs
  23. 23.  Health care agencies have very specific standards, rules and regulations governing the education and job responsibilities of the laboratory personnel  Lab. professionals are required to complete an authorized program and certification  Lab. Personnel need to observe/protect patient privacy
  24. 24. Safety  Occupational Safety and Health Administration(OSHA) began in 1970 as a legislation and subsequent rules that mandate increased attention to safety in workplaces  The Clinical laboratory has, physical, chemical and biological hazards
  25. 25. PPE  Employees in the clinical lab are required to use personal protective equipment:  Gloves  Mask  Gowns
  26. 26. Biohazards  In 1980 clinical laboratory safety training concentrated in protection from chemical, physical,and contagious diseases such as tuberculosis  The discovery of AIDS, increased in Hepatitis B virus(HBV) and Hepatitis C virus(HCV) brought an emphasis on biological safety  The term Biohazard came into use  A Biohazard symbol was adopted that indicates the presence of biological hazard or biohazardous condition
  27. 27. Evolution on Biological safety  By 1960 infectious patients were placed in ISOLATION rooms  1970-CDC outlined isolation guidelines and listed isolation categories  1985-in response to the increasing AIDS/HIV epidemic CDC adopted Universal Blood and Body fluids precautions, to be applied in all patients regardless of their infectious status  1987- Body substance Isolation, included all body fluid even if not visibly contaminated with blood
  28. 28. Evolution on Biological safety  1991-OSHA issued “Bloodborne pathogens standard”, not included on previous regulation  1996- CDC implemented “Standard Precautions” that includes a comprehensive set of safety guidelines for Health care workers rendering care to patients, this is the current terminology  To control nosocomial (inst. acquired) infections  Transmission-based precautions(additional practices for pathogens that spread by air, droplets, and contact 2001-OSHA revised the BBP(blood borne pathogen) standard to prevent accidental needle-sticks in the workplace
  29. 29. Standard Precautions Requires that every patient and every body fluid, body substance, organ, or unfixed tissue be regarded as potentially infectious  Hands wash(plain soap)  After touching body fluids and contaminated items, after removing gloves and between patient contact  Wear gloves  When touching blood/body fluids/secretions, wear clean gloves when touching mucous membranes and nonintact skin  Wear mask/eye protection/face shield  Activities that could generate splashes, spray of blood, body fluids , or secretions
  30. 30. Standard Precautions, cont. Patient care equipment  should be handled to prevent transfer of microorganisms to other patients and environment Linen  Handle, transport,and process in a manner to avoid contamination of clothing and other patients or environment Occupational health and blood-borne pathogens  Prevent injuries when using, handling, cleaning and disposing sharps  NEVER RECAP A USED NEEDLE  Do not removed used needle from syringe by hand  Disposed used sharps on puncture resistant containers
  31. 31. Standard Precautions,cont.  Use resuscitation devices as an alternative to mouth to mouth resuscitation  Patient placement  Use a private room for patients who can be a source of contamination or patients who are not expected to maintain hygiene or environmental control  Environmental control  Follow hospital procedures for routine care and cleaning/desinfection of any soiled device, equipment or environmental surface
  32. 32. General laboratory equipment  Centrifuges- spin samples at high speeds forcing the heavier particles to the bottom of the container,e.g..separating plasma and blood cells  Safety tips  Use Standard Precautions/PPE  Load must be balanced  Tubes must be capped during operation  Do not open the centrifuge while rotor is moving  Clean spills immediately with surface disinfectants
  33. 33. General laboratory equipment Autoclaves- use steam under pressure to sterilize medical/surgical instruments, or contaminated materials before disposal  Never open unless the chamber pressure reads zero  Use heat-proof gloves to remove items  When sterilizing liquids use loosely capped, heat resistant containers, no more than half full  Use an autoclave tray to prevent liquids from spilling
  34. 34. General laboratory equipment  Laboratory balances  Used to measure chemicals  Use PPE and chemical safety precautions  Be gentle, Balances are delicate equipment
  35. 35. General laboratory equipment  Other equipments  Refrigerators  Water baths  PH meters  Incubators  Thermometers  freezer
  36. 36. The Microscope  Is a delicate and expensive instrument , special care must be taken in its use  Various types of microscopes, two categories based on type of illumination  Light microscopes  Bright-field- stained specimens  Phase-contrast-unstained cells,urine sediment  Epi-fluorescence microscope,specimens treated with fluorescent dyes, syphilis, mycobacteria  Electron microscopes:provides greater magnification in medical research
  37. 37. Light microscope images A-stained cell seen with bright field microscope B-phase contrast image C-epi-fluorescence microscopy,Borrelia burgdorferi
  38. 38. Parts of the Microscope
  39. 39. Parts of the Microscope Oculars: monocular or binocular Objective lenses: attached to the revolving nose piece, at least 3 present: low, high dry, and oil immersion lenses Light condenser which focuses and directs light to the objectives, iris diaphragm that regulates the amount of light that strikes the object observed Field diaphragm:help align the light Coarse and fine adjustments:focusing knobs Stage:support for the object been viewed
  40. 40. Microscope safety  Safety  observe electrical safety rules  Glass slide handle with care to avoid breaking  Unfixed specimens should be treated with standard precautions,disinfect stage after use  QA  Scheduled maintenance should be performed and documented  Care and cleaning of lenses  Use only lens paper, clean lenses before and after each use  Do not allowed immersion oil to touch the low and high dry lenses  Transporting and storing
  41. 41. Transporting the Microscope
  42. 42. Using the Microscope  Use low power objective to locate and to view large objects  With the coarse adjustment knob bring the objective and the slide as close together as possible  While looking through the oculars, move the coarse adjustment knob to bring the objective and slide apart until the object on the slide comes into focus  Use the fine adj.knob to bring the image into sharp focus
  43. 43. Using the Microscope  If you need to use the high power(40x), to see cells and sediments, after initial focusing with the low power(20x), rotate the high power into position  Never use the coarse adjustment knob with high power, the distance between the objective and slide is very small and the slide could break.  Oil immersion lenses(100x) give the highest magnification of the bright field objectives
  44. 44. Using oil immersion lenses  After initially focusing with the low power, rotate the objective to the side and place a small drop of immersion oil on the slide  The oil immersion objective is rotated into the drop of oil been careful no other objective touch the oil  use only fine adjustment knob with oil  Condenser should be all the way up  Maximum light source  Open the iris diaphragm to the maximum
  45. 45. After using the Microscope  Always switch to the low magnification objective  With lens paper clean the oil immersion objective, stage and condenser if oil has become in contact with it  Turn the light source off  Unplug the microscope  Store in proper location or cover as appropriate
  46. 46. Calculate Magnification  Degree of magnification on the ocular multiplied by the degree of magnification on the objectives Example: 10x(ocular) x 100x(oil immersion)= 1000x The object viewed would be magnified 1000 times its original size Resolving power: the ability of a microscope to produce separate images of closely spaced details in the object being viewed
  47. 47. Blood collection  Capillary puncture: small amount of blood collected for glucose, K, electrolytes, Hgb, Htc, Plt count, or when a larger sample is difficult to obtain as in newborns  Routine venipuncture: most common method of obtaining blood, a superficial vein is punctured with a hypodermic needle and blood is collected into a syringe or vacuum tube
  48. 48. Capillary Puncture  Safe  Quick  Small amount of blood  Increased use  Point-of-care testing (POCT)  Physician Office Laboratories
  49. 49. Capillary Puncture Sites  Fingertip  Great toe  Heel
  50. 50. Capillary Puncture Sites
  51. 51. Lancets  Sterile  Single-use  Different lengths
  52. 52. Collection Containers
  53. 53. Procedure
  54. 54. Routine Venipuncture  Phlebotomy  Superficial vein  Large sample of blood  Skill and experience  Preserve vein integrity
  55. 55. Venipuncture Supplies  Needles  Various safety designs  21 ga, 1 inch  Needle holders  Phlebotomy tray
  56. 56. Venipuncture Supplies
  57. 57. Venipuncture Supplies  Vacuum tubes and anticoagulants  Sizes  Stopper color:  Red: no anticoagulant, to collect serum for blood chemistries and serology tests  Lavender: containing EDTA for hematologycal and blood typing tests(ethylenediaminetetraacetic acid )  Green: contains heparin, for lymphocytes studies and special chemistry  Light blue: sodium citrate for coagulation studies  Gray :potasium oxalate, for glucose and legal alcohol  Black: for westergren ESR  Draw exact amount
  58. 58. Safety Precautions  Observe standard precautions  Wear gloves and other PPE  Never recap needles  Use proper technique  Avoid  Hemoconcentration: do not leave tourniquet in place for more than 1-2 minutes  Hemolysis: do not shake tubes, mix by gently inverting a few times
  59. 59. Select Equipment
  60. 60. Patient Preparation  Patient I.D.  Explain procedure  Support patient and arm  Be prepared! for any sudden reaction from the patient, or occasional patient who may faint
  61. 61. Patient Preparation
  62. 62. Apply Tourniquet •3-4 inches above elbow •Use quick release tie
  63. 63. Identify Suitable Vein  Veins commonly used  Median cubital  Basilic  Cephalic  Palpate vein: carefully inspect both arms to find the better site
  64. 64. Perform Venipuncture  Alcohol-cleanse site, let air dry, do not touch the site after cleaning  Observe bevel up  Anchor vein with thumb 1inch below the puncture site  Enter vein in the same direction of it, in a15-25 degree angle, in a smooth motion  Insert vacuum tube  Clot tube first  Invert anticoagulant tubes softly 5-7 times
  65. 65. Perform Venipuncture
  66. 66. Adverse situations  In case of patient developing a large hematoma while venipuncture procedure is being done, withdraw the needle, apply pressure, and intent the procedure in a different site  In case of failure to obtain the blood, ask the patient permission for a second intent, if he agrees try in a different site  After the second non-productive intent,inform the patient and find another person to draw the specimen
  67. 67. Complete Procedure  Activate safety feature  Immediate disposal  Label tubes before leaving the room  Patient care
  68. 68. Patient care  The tourniquet is always release before needle is withdraw  Gauze should be applied over the puncture site and pressure maintained for 1-3 minutes or until bleeding stops  Ask patient to keep arm extended  Offer a small bandage if necessary
  69. 69. In Case of Accident  Immediately clean exposed area  Flood with water  Clean with antiseptic soap  Report immediately to supervisor  Seek medical attention
  70. 70. Label the samples  Must contain patient information  Name  Date of birth  Date and time of collection  And initials of the person drawing the blood  Tubes should never be prelabeled to avoid using the prelabeled tube in the wrong patient  Make sure the tubes are clean and no blood has contaminated the outer part of the tubes  Place specimen in a biohazard labeled bag and proceed as required by the institution
  71. 71. selecting tests to use:  Test selections are based on :  subjective clinical judgment,  national recommendations,  and evidence-based health care.  Often diagnostic tests or procedures are used as predictors of surgical risk or morbidity and mortality rates because, in some cases, the risk may outweigh the benefit.
  72. 72. selecting tests to use: 1.Basic screening (frequently used with wellness groups and case finding) 2. Establishing (initial) diagnoses 3. Differential diagnosis 4. Evaluating current medical case management and outcomes 5. Evaluating disease severity
  73. 73. 6. Monitoring course of illness and response to treatment 7. Group and panel testing 8. Regularly scheduled screening tests as part of ongoing care 9. Testing related to specific events, certain signs and symptoms, or other exceptional situations (eg, infection and inflammation , sexual assault, drug screening, postmortem tests, to name a few)
  74. 74. groups and case finding)  Cervical Papanicolaou (Pap) test  Yearly for all women 18 years of age; more often with high-risk factors (eg, dysplasia, human immunodeficiency virus [HIV], herpes simplex); check for human papillomavirus (HPV), chlamydia, and gonorrhea using DNA
  75. 75. Establishing (initial) diagnoses  Serum amylase  In the presence of abdominal pain, suspect pancreatitis  Thyroid-stimulating hormone (TSH) test  Suspicion of hypothyroidism, hyperthyroidism, or thyroid dysfunction in patients 50 years of age
  76. 76. Differential diagnosis  Chlamydia and gonorrhea  In sexually active persons with multiple partners; monitor for pelvic inflammatory disease
  77. 77. Evaluating current medical case management and outcomes  Tuberculosis (TB) blood test QuantiFERON Gold TB  Blood test to assess TB exposure in risk population  Syphilis serum fluorescent treponemal antibody (FTA) test  Positive rapid plasma reagin (RPR) test result
  78. 78. Grading Guidelines for Scientific Evidence  A. Clear evidence from all appropriately conducted trials  Measure plasma glucose through an accredited lab to diagnose or screen for diabetes  B.Supportive evidence from well-conducted studies or registries  Draw fasting blood plasma specimens for glucose analysis
  79. 79.  C.No published evidence; or only case, observational, or historical evidence •  Self-monitoring of blood glucose may help to achieve better control  E.Expert consensus or clinical experience or Internet polls  Measure ketones in urine or blood to monitor and diagnose diabetic ketoacidosis (DKA) (in home or clinic)
  80. 80. The diagnostic testing model  incorporates three phases:  pretest,  emphasis on appropriate test selection,  obtaining proper consent,  proper patient preparation,  individualized patient education,  emotional support, and effective communication.  These interventions are key to achieving the desired outcomes and preventing misunderstandings and errors.
  81. 81.  Intratest Phase: Elements of Safe, Effective, Informed Care  Posttest Phase: Elements of Safe, Effective, Informed Care
  82. 82. The clinical value of a test is related to  sensitivity, specificity, and the incidence of the disease in the population tested.  Sensitivity and specificity do not change with different populations of ill and healthy patients  The predictive value of the same test can vary significantly with age, gender, and geographic location.
  83. 83.  Specificity refers to the ability of a test to identify correctly those individuals who do not have the disease.  The division formula for specificity is as follows:  Specificity%=persons w/o dis.who test neg./total # of persons w/o dis. X 100
  84. 84.  Sensitivity refers to the ability of a test to correctly identify those individuals who truly have the disease.  The division formula for sensitivity is as follows:  Sensitivity% = persons with dis.who test positive/ total # persons tested with disease x 100
  85. 85.  Incidence refers to the number of new cases of a disease, during a specified period of time, in a specified population or community.  Prevalence refers to the number of existing cases of a disease, at a specific period of time, in a given population.
  86. 86. Predictive values Predictive values refer to the ability of a screening test result to correctly identify the disease state. The predictive value of the same test can be very different when applied to people of differing ages, gender, geographic locations, and cultures.
  87. 87. test outcome deviations Minimize test outcome deviations  following proper test protocols.  Make certain the patient and his or her significant others know what is expected of them.  Written instructions are very helpful.
  88. 88. Reasons for deviations may include the following  Incorrect specimen collection, handling, storage, or labeling  Wrong preservative or lack of preservative  Delayed specimen deliver
  89. 89. Reasons for deviations may include the following  Incorrect or incomplete patient preparation  Hemolyzed blood samples  Incomplete sample collection, especially of timed samples  Old or deteriorating specimens
  90. 90. Patient factors that can alter test results may include the following  Incorrect pretest diet  Current drug therapy  Type of illness.  Dehydration  Position or activity at time of specimen collection
  91. 91. Patient factors that can alter test results may include the following  Postprandial status (ie, time patient last ate)  Time of day  Pregnancy  Age and Gender
  92. 92. Patient factors that can alter test results may include the following  Level of patient knowledge and understanding of testing process  Stress  Nonadherence or noncompliance with instructions and pretest preparation  Undisclosed drug or alcohol use
  93. 93. avoid costly mistakes  Communication errors account for more incorrect results than do technical errors.  Properly identify and label every specimen as soon as it is obtained.
  94. 94. Educate the patient and family  Educate regarding the testing process and what will be expected  Record the date, time, type of teaching, information given, and person to whom the information was given.
  95. 95. Educate the patient and family  Giving sensory and objective information that relates to what the patient will likely physically feel and the equipment that will be used is important so that patients can envision a realistic representation of what will occur.
  96. 96. Educate the patient and family  Avoid technical and medical jargon  and adapt information to the patient's level of understanding.  Slang terms may be necessary to get a point across.
  97. 97. Educate the patient and family  Encourage questions and verbalization of feelings, fears, and concerns  Do not dismiss, minimize, or invalidate the patient's anxiety  Develop listening skills, and be aware of nonverbal signals (ie, body language)
  98. 98. Educate the patient and family  Above all, be nonjudgmental.  Emphasize that there is usually a waiting period (ie, turn-around time) before test results are relayed back to the clinicians and nursing unit.  Offer listening, presence, and support during this time of great concern and anxiety
  99. 99. Educate the patient and family  Because of factors such as anxiety, language barriers, and physical or emotional impairments, the patient may not fully understand and assimilate instructions and explanations
  100. 100. Educate the patient and family  To validate the patient's understanding of what is presented, ask the patient to repeat instructions given to evaluate assimilation and understanding of presented information.
  101. 101. normal or reference values  Normal values are those that fall within 2 standard deviations (ie, random variation) of the mean value for the normal population.  Normal ranges can vary to some degree from laboratory to laboratory. Frequently, this is because of the particular type of equipment used
  102. 102. normal or reference values  The reported reference range for a test can vary according to the laboratory used, the method employed, the population tested, and methods of specimen collection and preservation.
  103. 103. normal or reference values  Interpretation of laboratory results must always be in the context of the patient's state of being.  Circumstances such as hydration, nutrition, fasting state, mental status, or compliance with test protocols are only a few of the situations that can influence test outcomes.
  104. 104. clinical laboratory data values  may be reported in conventional units, SI units(Systéme International (SI) units), or both  The SI system uses seven dimensionally independent units of measurement to provide logical and consistent measurements
  105. 105. clinical laboratory data values SI concentrations are written as amount per volume  (moles or millimoles per liter)  rather than as mass per volume (grams, milligrams, or milliequivalents per deciliter, 100 milliliters, or liter)
  106. 106.  Numerical values may differ between systems or may be the same.  For example, chloride is the same in both systems: 95 to 105 mEq/L (conventional)  and 95 to 105 mmol/L (SI).
  107. 107. Recognize margins of error  possibility exists that some tests will be abnormal owing purely to chance  because a significant margin of error arises from the arbitrary setting of limits.  Moreover, if a laboratory test is considered normal up to the 95th percentile, then 5 times out of 100, the test will show an abnormality even though a patient is not ill
  108. 108. Cultural Sensitivity  Many cultures have diverse beliefs about diagnostic testing that requires blood sampling  Preserving the cultural well-being of any individual or group promotes compliance with testing and easier recovery from routine as well as more invasive and complex procedures
  109. 109. END