Laboratory Medicine

Question 1

Anatomical Pathology

Answer 1

Cytopathology
Autopsy
Surgical

Question 2

Laboratory Medicine

Answer 2

Clinical Pathology-
Chemistry
Micro
Transfusion
Heme
Cytogenetics

Question 3

How can Inappropriate use of laboratory medicine negatively affect patient care/outcome?

Answer 3

Delayed Decisions
Prolonged Hospital stays
Missed/delayed diagnoses
Increased cost

Question 4

Diagnostic Test

Answer 4

Used to determine the presence or absence of disease WHEN A SUBJECT SHOWS SIGNS OR SYMPTOMS OF THE DISEASE

Question 5

Screening Test

Answer 5

Identifies ASYMPTOMATIC INDIVIDUALS who may have the disease

Question 6

Reference Material

Answer 6

A sample of the analyze with a precisely known composition

Question 7

Reference Measurement Procedure (RMP)

Answer 7

The “gold-standard” measurement system for a particular analyte.

Question 8

Secondary Measurement Procedures

Answer 8

Validated by reference materials and using the RMP.

Usually less sophisticated but more easily implemented.

Question 9

Pre-Analytic Phase of Diagnostic Testing

Answer 9

Develop a question
Select a laboratory test
Order the test
Collect the specimen

Question 10

Analytic Phase of Diagnostic Testing

Answer 10

Sample prepared for analysis
Sample is analyzed
Result is Verifired

Question 11

Post-Analytic Phase

Answer 11

Result is Reported
Test result is interpreted in the context of the clinical case
Action is taken
Patient Care is affected

Question 12

What phase of Diagnostic Testing accounts for most errors?

Answer 12

Pre-Analytic Phase

Question 13

Which phase of diagnostic testing has the LEAST amount of errors?

Answer 13

Analytic Phase

Question 14

Accuracy vs Precision

Answer 14

Accurate means close to true

Precision is consistency

Question 15

Guassian Distribution

Answer 15

Bell curve, Central 95% is “Normal range”

Question 16

Note about “abnormal normals” and “normal abnormals”

Answer 16

Test results being in or out of the normal range are NOT ALWAYS indicative of healthy/unhealthy results. Some patients normals may be outside Normal range and vice versa

Question 17

Sensitivity (Definition and Formula)

Answer 17

Ability of a test to detect disease

Of all people with disease, how many will test positive

Question 18

Specificity (Definition and Formula)

Answer 18

Ability of a test to detect the absence of disease

In everyone without disease, how many get a negative test

Question 19

Receiver Operator Characteristic (ROC) Curve

Answer 19

Graphical technique used to compare diagnostic test performance at different cut-offs

True Positive vs False Positive

Question 20

Predictive Value

Answer 20

Likelihood that the result indicates presence or absence of disease

Question 21

Positive Predictive Value PV (+)

Answer 21

What’s the chance that the positive result indicates the presence of disease

True Positives/ (all positives)

Question 22

Negative Predictive Value PV (-)

Answer 22

What’s the chance that the negative result indicates absence of disease?

True Negative/ (All negatives)

Question 23

Point of Care Testing

Answer 23

Tests that can be performed at the bedside (blood/urine usually)

Usually uses transportable or handheld instruments

Question 24

Virchow vs Rokitansky Autopsy

Answer 24

Virchow: Organs one-by-one

Rokitansky: organs removed en masse

Question 25

Why are autopsies performed?

Answer 25

Medical Audit Education (medical students, clinicians, etc.) Discovery (unexplained, unexpected) Investigations (medical/legal research)

Question 26

Have autopsy rates gone up or down over the years and why?

Answer 26

DOWN Liability, unnecessary due to newer/accurate testing, lack of interest