introduction of clinical laboratory science

TAPESHWAR YADAV(LECTURER)BMLT, DNHE,

M.SC. MEDICAL BIOCHEMISTRY

Clinical or Medical Laboratory

A – A good student is liked by teacher

G – Greets everyone with smileO – ObedientO – On time for collegeD – Dresses neatly

S – Studies with interestT – Treats everyone with smileU – Understands everythingD – Does daily home workE – Eager to know new thingsN – Never misbehavesT – Talks little in class

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).

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.

Contd…

Immunology, Serology, Histopathology, Immunohematology and Molecular biology and others.

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.

Clinical or Medical Laboratory

Laboratories that perform chemical and microscopic tests on:

bloodother body fluidstissues

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

Government Laboratories- state Premarital blood testing PKU testing in newborns Fungi,virus, and mycobacteria culture

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

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

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

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

Laboratory personnel

General supervisor for each area Testing personnel:

Medical Technologists(MT/CLS) Medical Lab.Technicians(MLT/CLT) Medical assistants/nursing staff(POLs)

Departments of the Clinical Laboratory

Clinical Chemistry Hematology Microbiology Blood Bank Supports Services (Phlebotomy/Specimen

Processing)

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

Hematology

Studying of the cellular components of the blood

Quantitative or Qualitative Coagulation Urinalysis Special hematology

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

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

Support Services

Phlebotomists Accessioning

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

Quality Assessment System

QA.is 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

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

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

PPE

Employees in the clinical lab are required to use personal protective equipment:

Gloves Mask Gowns

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

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

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

Standard PrecautionsRequires 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

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

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

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


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


Laboratory balances Used to measure chemicals Use PPE and chemical safety precautions Be gentle, Balances are delicate equipment


Other equipments Refrigerators Water baths PH meters Incubators Thermometers freezer

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

Light microscope images

A-stained cell seen with bright field microscopeB-phase contrast imageC-epi-fluorescence microscopy,Borrelia burgdorferi

Parts of the Microscope

Parts of the Microscope

Oculars: monocular or binocularObjective 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 lightCoarse and fine adjustments:focusing knobsStage:support for the object been viewed

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

Transporting the Microscope

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

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

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

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

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

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

Capillary Puncture Safe Quick Small amount of blood Increased use

Point-of-care testing (POCT) Physician Office Laboratories

Capillary Puncture Sites

Fingertip Great toe Heel

Capillary Puncture Sites

Lancets

Sterile Single-use Different lengths

Collection Containers

Procedure

Routine Venipuncture

Phlebotomy Superficial vein Large sample of blood Skill and experience

Preserve vein integrity

Venipuncture Supplies

Needles Various safety designs 21 ga, 1 inch

Needle holders Phlebotomy tray


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

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

Select Equipment

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

Patient Preparation

Apply Tourniquet

•3-4 inches above elbow•Use quick release tie

Identify Suitable Vein Veins commonly used

Median cubital Basilic Cephalic

Palpate vein: carefully inspect both arms to find the better site

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

Perform Venipuncture

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

Complete Procedure

Activate safety feature Immediate disposal Label tubes before leaving the room Patient care

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

In Case of Accident

Immediately clean exposed area Flood with water Clean with antiseptic soap

Report immediately to supervisor Seek medical attention

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

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.

selecting tests to use:

1.Basic screening (frequently used with wellness groups and case finding)

2. Establishing (initial) diagnoses3. Differential diagnosis4. Evaluating current medical case

management and outcomes 5. Evaluating disease severity

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)

Basic screening (frequently used with wellness 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

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

Differential diagnosis

Chlamydia and gonorrhea In sexually active persons with multiple partners;

monitor for pelvic inflammatory disease

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

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

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)

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.

Intratest Phase: Elements of Safe, Effective, Informed Care

Posttest Phase: Elements of Safe, Effective, Informed Care

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.

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

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

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.

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.

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.

Reasons for deviations may include the following

Incorrect specimen collection, handling, storage, or labeling

Wrong preservative or lack of preservative Delayed specimen deliver

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

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


Postprandial status (ie, time patient last ate)

Time of day Pregnancy Age and Gender


Level of patient knowledge and understanding of testing process

Stress Nonadherence or noncompliance with

instructions and pretest preparation Undisclosed drug or alcohol use

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.

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.


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.


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.


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)


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


Because of factors such as anxiety, language barriers, and physical or emotional impairments, the patient may not fully understand and assimilate instructions and explanations


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.

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


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.


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.

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

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)

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).

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

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

introduction of clinical laboratory science

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