LMP301H1 Lecture Notes - Lecture 1: Hyponatremia, Hyperglycemia, Respiratory Acidosis

140 views9 pages
14 Sep 2016
School
Course
Professor
LMP301
Introduction to the Biochemistry of Human Disease
Lecture 1 - Introduction
Disease - sickness with characteristic symptoms; response to injury
A diagnosis of disease requires objective evidence
Biochemical tests use body fluids, are relatively non-invasive, safe, and fast and accurate
Objectives of laboratory medicine
1. Define (diagnosis)
2. Predict (prognosis)
3. Monitoring
4. Find cause (etiology)
5. Screening
Mortality: causing death or reducing lifespan
Morbidity: impairs quality of life
Prevalence: number of cases of disease in a population
Incidence: number of new cases/unit time in a population
Endemic: most of the population has the disease
Epidemic: widespread occurrence of disease in a population where it’s rare
Classifications of disease:
Hereditary genetic etiology
Congenital - from birth
Injury physical or chemical stress
Infections often bacterial or viral
Inflammation
Vascular
Nutritional caused by diet
Metabolic abnormal production of enzymes/other molecules
Tumors
Iatrogenic
Psychological
Idiopathic
Purpose of testing:
Diagnostic testing
Screening for risk of a disease (e.g. heart disease, cancer)
Exclusion test
Monitoring
Others…
Unlock document

This preview shows pages 1-3 of the document.
Unlock all 9 pages and 3 million more documents.

Already have an account? Log in
Lecture 2 Lab Tests
Labs in Ontario are funded by MOHLTC. Labs are divided into different areas. Turn-around time, cost,
technical expertise, and clinical need are things to consider.
Types of markers:
1. Physiological (normal range in a healthy person, tightly regulated by body)
2. Disease markers (not normally present or only in minute amounts, not regulated by body,
normally excreted)
Patient self-testing and point-of-care (POC) testing is convenient, but often costly and lacking in QC.
Testing process:
1. Pre-analytical patient preparation (e.g. fasting or diet, medications, patient factors such as
age, sex, race, pregnancy, stress), sample collecting, transporting, processing
2. Analytical sample analysis
3. Post-analytical interpretation and communication of result
Specimen type:
Red cap: serum
Green: plasma + heparin
Grey: plasma + sodium oxalate
Purple: plasma + EDTA
Sampling errors include technique, errors in timing, incorrect sampling site, etc.
Case 1: woman on diuretics shows high serum K+, but physician is not concerned
This is normal range for patients on diuretic medication.
Precise: values agree with each other, but not necessarily close to true value (usually more important)
Accurate: values close to true value
Interferences may decrease precision and accuracy
Unlock document

This preview shows pages 1-3 of the document.
Unlock all 9 pages and 3 million more documents.

Already have an account? Log in
Lecture 3 Cases
The normal interval is the central 95% of a distribution from a healthy sample of 120+ individuals.
However, factors such as age, sex, and race may differ the best healthy range is the patient’s own.
This 95% interval = 2.8 x [(analytical variance)2 +(biological variance)2]
Test interpretation:
True positive
True negative
False positive
False negative
o Where true/false determines whether the test was right and positive/negative
determine the test result.
Clinical sensitivity = TP/(TP+FN)
Detects a disease when it is actually present
SnNout = SeNsitivity test, Negative result, rule OUT disease
Clinical specificity = TN/(TN+FP)
Detects absence when the disease is not present
SpPin = SPecificity test, Positive result, rule IN disease
Predictive value of + test = TP/(TP+FP)
Probability of test detecting a disease when it’s present
Predictive value of test = TN/(TN+FN)
Probability of test detecting absence when it’s absent
Efficiency = TP+TN/(TP+TN+FP+FN)
Accurately make a conclusion
Receiver operator characteristic (ROC) curves balance sensitivity and specificity
y-axis = true positive rate (sensitivity)
x-axis = false positive rate (1-specificity)
upper left corner is best
Unlock document

This preview shows pages 1-3 of the document.
Unlock all 9 pages and 3 million more documents.

Already have an account? Log in

Get OneClass Notes+

Unlimited access to class notes and textbook notes.

YearlyBest Value
75% OFF
$8 USD/m
Monthly
$30 USD/m
You will be charged $96 USD upfront and auto renewed at the end of each cycle. You may cancel anytime under Payment Settings. For more information, see our Terms and Privacy.
Payments are encrypted using 256-bit SSL. Powered by Stripe.