Clin Path Lec 1 - Generalities

CLINICAL PATHOLOGY LECTURE 1 – GENERALITIES – Dr. Pascual USTMED ’07 Sec C - AsM BASIC SCIENCE research education

MEDICAL PRACTICE diagnosis therapy prognosis quality assurance Computational Science Management techniques industry

Schematic outline of activities in clinical labs ADMINISTRATION PATIENT CARE SERVICE Indications and selection

Technology and generation

Interpretation and translation

Teaching Research BIOHAZARD - ORANGE National fire protection rating system

FIRE red HEALTH blue

flammability - red health hazard - blue reactivity - yellow REACTIVITY yellow

OTHER white

Review BIOSTAT Result of test + Total

Diseas e a (TP) c (FN) a+c

not disease b (FP) d (TN) b+d

sensitivity =

a a+c

x 100

specificity =

d b+d

x 100

false positive =

b b+d

x 100

false negative=

c a+c

x100

Total a+b c+d a + b + c +d

sensitivity of the test (++) refers to the proportion of people with disease who have a positive test result for the disease specificity of the test (--) refers to the proportion of people without the disease who have negative test result for the disease false positivity of the test (-+) refers to the proportion of people without the disease but have positive test result for the disease false negativity of the test (+-) refers to the proportion of people with the disease but have negative test result for the disease

Components of Accuracy 1. positive predictive value - refers to the probability that the patient has the disease given a positive test result 2. negative predictive value - refers to the probability that the patient does not have the disease given a negative test result accuracy =

a+d a+b+c+d

x 100

positive predictive value =

a a+b

x 100

negative predictive value =

d c+d

x 100

Process of test selection and interpretation of results Test request

interpretation

written order

report calculation specimen

specimen prep

measurement

patient prep turn around time - the sooner the better Interpretation and decision making - normal, abnormal Indications or reasons for ordering lab measurements or examinations 1. to confirm clinical impression or establish diagnosis 2. to rule out diagnosis 3. to monitor therapy (management guide) 4. to establish prognosis 5. to screen for or detect disease Role of Clinical Pathogenesis 1. Internal - Quality control a. assess procedure of test i. sensitivity and specificity ii. duplicability iii. turn around time b. assess applicability of latest equipment with regards to i. need of the hospital ii. acceptability of equipment iii. economical 2. External a. active participation in various hospital committees I. infectious control committees 1. antimicrobial and sensitivity pattern of the hospital 2. education of hospital personnel 3. safety procedure to be implemented in the hospital ii. blood transfusion committees 1. SOP for transfusion 2. education 3. safety transfusion and proper use of blood and its components iii. medical audit committee 1. proper use of laboratory requests 2. education of training residents Illustration of pathogenic reasoning. Cause-effect reasoning for extrahepatic obstruction caused by a common bile duct stone +AST +ALT

pain + Bili + LP +GGTP

distension CBD stone

obstruction

cholestasis

stasis

enzyme release cell necrosis

cholangitis infection

bacteria fever leukocytosis

positive blood culture

Case protocol ECP is male, BS Bio student, UST, came in because ____________ CC - Jaundice HPI - few days prior to admission, developed moderate grade fever, abdominal pain, anorexia; subsequently, patient noticed his urine to be highly colored PPE - conscious, coherent, cooperative fairly nourished, febrile skin rashes, yellowish discoloration of skin PPH - stages in boarding house along university belt. takes meals on several eateries regularly. recently donated blood Clinical impression _____________________________ basis 1. 2. 3. Lab diagnosis 1. blood exam 2. urine 3. stool 4. serologic 5. radiology 6. histopathology Final clinical diagnosis________________ therapy mortality or mobidity - post mortem FINAL anatomic diagnosis ______________________

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