1. the role of gp in lab.medicine.ppt

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The Role of GP In

Laboratory Medicine



Health care delivery involves many different

disciplines and specialities diagnosticevaluation/services laboratory test.



Human body

Consist of many systemsSystem is : a set or series of interconnectedor interdependent parts or entities(organs), that function together in acommon purpose or produce resultsimpossible of achievement by one of themacting or operating alone.

System consist of many organsOrgan consist of tissuesTissue consist of cells



E.g :Neurobehaviour systemRespiratory systemCardiovascular system

Gastrointestinal systemGenitourinary systemReproductive systemDermato musculoskeletal systemetc



Respiratory system

Organs:nose, throat, trachea, bronchus,

bronchioles, lung, etc.Tissues:muscle, connectiveCells:epithel



Systems work properly healthy human

System(s) work improperly unhealthy(sick/ill) :

Signs & symptoms (e.g fever/febris)

Asymptomatic (e.g increase of bloodglucose level/Diabetes Mellitus).



4 aspects of disease

1. Causes (disease agent, etiology)2. Mechanism of its development

(pathogenesis, pathophysiology)3. Morphologic changes4. Clinical significance



Sign

Definition :An indication of the existence of somethingAny objective evidence of diseasesuch evidence as is perceptible to the examiningphysician

Examples :

Anemic conjunctiva or icteric sclera



Symptom

Definition :any subjective evidence of disease or ofpatient’s condition. Examples :Fatigue, nausea



Healthy people could become ill by one oranother reasons called etiology.

Mechanism of diseases is calledpathophysiology/pathogenesis



Etiology

The study or theory of the factors that causedisease and the method of their introduction

to the host the cause of disease.



Pathophysiology/pathogenesis

Pathophysiology : the physiology ofdisordered function.

Pathogenesis :the development of morbid conditions or

disease; more specifically, the cellular eventsand reactions and other pathologicmechanisms occurring in the development ofdisease.



Pathology

Branch of medicine which treats of theessential nature of disease, especially of thestructural and functional changes in tissues

and organs of the body which cause or arecaused by disease.

Cellular and Clinical Pathology



Cellular (Anatomical Pathology):Regards the cells as a starting points of thephenomena of disease and that every celldescends from some preexisting cell.

Clinical Pathology:Pathology applied to the solution of clinicalproblems, especially the use of laboratorymethods in clinical diagnosis.



Basicbiological &

physicalsciences

Medical

principles

ClinicalPathology

-Modern equipment-Reagents

-IT

-Industry/Vendor



Disease : disruption of normal bodyfunctionAnything which disrupts homeostasis maybe viewed as a disease agent ( etiology ).Disease agents :

Infectious agentsPhysical and chemical agentsInherited genetic alterationsAcquired mutation and cancerMalnutritionInflammation and autoimmunity



Healthy Human Sick/illPathophysiology

Etiology

- Symptoms : fever, headache

- Signs : fever

- Lab.evaluations : leukopenia,

culture (+), Widal (+)

S.typhi

Endotoxin

Diagnosis : Typhoid fever



Clinical Pathology

Clinical Hematology

Clinical Chemistry

Clinical Microbiology

Clinical Immunology

Blood

• Blood

• Urine• Stool

• CSF

• Trans/Exudate• etc blood

Samples :



Clinical Hematology

Parameters to beevaluated :

Hemoglobin

Leucocyte count

Platelet count

Hematocrit

etc

Manually

Automatically

AutomaticHematology Analyzer



Clinical Chemistry

Blood

Urine

Parameters to

be evaluated

Glucose, cholesterol,triglyceride, cardiac

enzyme, etc

Glucose, protein,bilirubin, pregnancy

test, etc



Clinical Microbiology

Blood

Swab

Parameters to

be evaluated

Blood cultures ofmicroorganisms

Direct

preparation ofmicroorganisms



Clinical Immunology

Blood Parameters to be evaluated

Hepatitis markers (A, B)

TORCH

HIV

Dengue

Typhoid

etc



Purposes of Laboratory Tests

1. Screening2. To confirm a diagnosis

3. To monitor patient’s disease status



The purpose and function of Clinical Pathology

1. Screening2. Confirming or rejecting diagnosis3. Monitoring:

Response to treatment (providing guidelines inpatient management)Respons to drug (level)Measure progression or regression of a disease

4. Establishing a prognosis



Screening

1. Mass screening:• Phenylketonuria in newborn• Hepatitis V in blood transfusion donor

2. Screening asymptomatic patients: – Blood glucose, cholesterol in mediecal check up

3. Screening symptomatic patients:



Symptomatic patients

1. Non-specific complaints2. Specific problem already identified



Non-specific complaints

1. Battery of chemistry tests2. Complete Blood Count (CBC)3. Routine urinalysis

Problem: positive test false positive results

Solution: repeat abnormal test on a differentsample



Detecting disease throughcase finding or screening

Screening of the donors forHepatitis B Virus :

HBsAg :

HBsAg : (+)

HBsAg : (-)

Donors rejected (case findings)

Donors accepted (screeninghealthy subjects)



Specific complaint (problem)

Defined set of differential diagnosis

Screening test to spare down differential diagnosis (high

sensitivity for a disease)

Test negative disease excluded

Test positive True positive

False positive use test(s) with high

specificity



Confirming or rejecting diagnosis

Patient with fever

Differential diagnosis:• Dengue• Typhoid

Laboratory results:• Dengue (-)• Typhoid (+)

Final diagnosis:• Dengue reject• Typhoid confirm



Providing guidelines in patient management

Patients with Diabetes Mellitus

2HPP* Blood glucose levels :

Mr.A : still high (300 mg/dL) Mrs.B : normal (110 mg/dL)

Increase Oral Anti Diabeticdose

Maintain Oral Anti Diabeticdose

*2HPP : 2 hours post prandial (after meal)



Establishing prognosis

Patients with acute viral hepatitis

Cellular liver enzymes : ALT* level

Mr.X : high (400 IU) Mrs.Y: very high (1400 IU)

Prognosis : good Prognosis : bad

*ALT : Alanine aminotransferase



Monitoring follow up therapy

Patient with urinary tract infection

After finished 1 cured dosage of

certain antibiotic

Urine culture still (+)

Change antibiotic withthe sensitive one



Order of testing

• From cheap to costly

• From less to more risky

•From simple to more complex

Within the constrains of time, risk, and cost, try todo the test or procedure with the most efficiency assoon as possible highest: sensitivity, specificityand predictive value



Perfect Test

1. Accurate (teliti)2. Precise (keterulangan tinggi)3. Discriminating ( kemampuan membedakan)4. Pain free (tidak menyakitkan)5. Risk free (risiko kecil)

6. Inexpensive (murah)7. Useful (bermanfaat)



Phases of the Test

1. Pretest

2. Intratest3. Posttest

Elements of:

• Safe

• Effective

• Informative



Reference Intervals (value)

Sensitivity & specificityInterpreting & correlating abnormallaboratory values

Quality Control & Quality Assurance

Interpreting Laboratory

Result



Reference intervals

A set of values of a certain type ofquantity obtainable from a singleindividual or a group of individualscorresponding to a stated description

(Dybkaer)



This description must be spelled out andavailable if others are to used the referencevalues

For each type of quantity, a series ofreference group will be necessary, takinginto consideration : age, sex, ras,menstruation, previous diet and exercise,posture etc.

Example : Hemoglobin level (new bornbaby, infant, children, female adult, maleadult, elderly)

l l b l l ( d )



Example : Mean Hemoglobin level (g/dL)

Newborn : 16.5

1-3 days : 18.51 week : 17.5

2 weeks : 16.5

1 month : 14

2 months : 11.5

3-6 months : 11.5

0.5-2 years : 12

2-6 : 12.5

6-12 : 13.5

12-18 Female : 14

Male : 14.5

18-49 Female : 14

Male : 15.5



Sensitivity : indicates the frequency of positive test results in

patients with particular diseases.

Its positivity in disease expressed as percent

Example : The sensitivity of HIV test with 3 rd

generation of ELISA is 99.9 %.

Sensitivity & Specificity



Specificity : indicates the frequency of negative test results

in patients without the diseases.

Its negativity in health or absence of a

particular disease expressed as percent

Example : The specifitivity of HIV test with 3 rd

generation of ELISA is 98.5 %.

Sensitivity & Specificity



Major purpose of performing laboratorydetermination aids in the diagnosis &

management of :patients with disease

individual in health assessment

Interpreting & Correlating

Abnormal Laboratory Values



1. Explain abnormal lab.value (esp.those thatdo not seem correlate with one another.

2. Recommended/order lab.test that maylead to correct diagnosis.

3. Reveal the occurrence of laboratory error

Doctor has to :



Never rely on a single (out of reference range)value to make a diagnosis.

It is vital to establish a trend in values.

Example :

Single Sodium values of 30 mEq/L does not

necessarily indicate hyponatremia. It maybespurious and may reflect such factors as :

- improper phlebotomy technique

- laboratory variability

1

Fundamental Principles in

Interpretation of Values



Osler’s Rule

Especially if the patient is under the ageof 60 years, try to attribute allabnormal lab.findings to a single cause.

Only if there is no possible way tocorrelate all abnormal findings, shouldthe possibility of multiple diagnosis beentertained.

2



Thank you for your attention



Sequence of Tests

Depends on many situation:1. Critical – test with the highest yield is done,

even though there maybe some risks.2. Time-lower risk yield, less risky procedure

done first

Elements of Safe Effective and Informed care



Elements of Safe, Effective and Informed carePRETEST PHASE INTRATEST PHASE POSTTEST PHASE

Basic knowledge & ness.skill Basic knowledge & ness.skill Basic knowledge & ness.skill

Testing environments Infection control Abnormal test results

History & assessment Collaborative approaches Follow-up councelling

Reimbursement for d/ service Risk management Monitoring for complications

Methodology of testing Specimens and procedures & sedation effect

Interfering factors Equipment and supplies Test results availability

Avoiding errors Family presence IntegrationProper preparation Positioning for procedure Reverral & Treatments

Patient education Administr of drug & solution Follow-up care

Testing Protocols Management of environment Documentation, Record

Patient independence Latex sensitivity & allergy Keeping & Reporting

Test results Pain control, comfort measu- Guidelines for disclosureLaboratory reports Res, & patient Monitoring Patient responses to d/

Margins of error Sedation & analgesia Expected & unex/ outcomes

Ethics and the law

Patient’s bill of right & respon

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