Module 0 - Introduction

Question 1

What is the purpose of lab tests?

Answer 1

Screening of a disease
Diagnosis or differential diagnosis of a disease
-new disease
-recurring disease
Monitor/change drug therapy

Question 2

Accuracy

Answer 2

Extent to which the mean measure is close to the TRUE VALUE

Question 3

Precision

Answer 3

The agreement of results when the test is run multiple times on the same sample (reproducibility)

Question 4

Sensitivity

Answer 4

• Ability of a test identify positive results in a patient that actually has a disease
• This is also called the True Positive Rate

Question 5

SNOUT

Answer 5

Sensitivity, a negative test rules disease out

Question 6

What is the formula for sensitivity?

Answer 6

Sensitivity = True positives/(True positives + False negatives)

Question 7

Specificity

Answer 7

• Ability of a test to identify negative results in a patient who does NOT have a disease
• This is also called the True Negative Rate

Question 8

SPIN

Answer 8

Specificity, a positive test rules disease in

Question 9

What is the formula for specificity?

Answer 9

Specificity = True negatives/(True negatives + False positives)

Question 10

What is a Predictive Value?

Answer 10

Assesses a test’s reliability considering sensitivity, specificity and prevalence of disease in a population (how good is this test for predicting disease?)

Question 11

What is the Positive Predictive Value?

Answer 11

-The proportion of patients with positive test results who are correctly diagnosed as having a disease

Question 12

What is the Negative Predictive Value?

Answer 12

-The proportion of patients with negative test results who correctly do not have a disease

Question 13

see slide 17

Answer 13

cool cool

Question 14

What is a reference range?

Answer 14

A reference range or normal range reported on lab reports will encompass 95% of the population.
Ex. Potassium reference range = 3.5 - 5.0 mmol/L

**Reminder: 5% of the population (2.5% on each side) WILL NOT fall within reference range! Clinical presentation and clinical judgement is important!

Question 15

What is a qualitative test?

Answer 15

A qualitative test reports an outcome that is positive or negative (no numbers, simply a yes or no)

Question 16

What is quantitative test?

Answer 16

A quantitative test reports an exact numerical measurement. These usually have reference ranges when reported by the lab

Question 17

Qualitative or Quantitative?

Home pregnancy test

Answer 17

Qualitative

Question 18

Qualitative or Quantitative?

Total cholesterol

Answer 18

Quantitative

Question 19

Qualitative or Quantitative?

HIV test

Answer 19

Qualitative

Question 20

Qualitative or Quantitative?

White Blood Cell Count

Answer 20

Quantitative

Question 21

Qualitative or Quantitative?

Urine Dipstick Test

Answer 21

Semi - Quantitative:

Yes or no answer with an estimated amount

Question 22

What 5 things should you consider when deciding to order a lab test?

Answer 22

• Necessity
• Knowledge to act on abnormal result
• Risks and Costs
• Special Instructions to give pt prior to test
• Lab Forms (do you have all the information to fill out the lab requisition)

Question 23

Necessity

Answer 23

Is the lab test clinically necessary?
-Will it change anything clinically if the lab value comes back as abnormal?
-Will it add new info to the clinical picture?
If yes - order it
If not - reevaluate

Question 24

Knowledge

Answer 24

Do I have enough knowledge to act on the lab value if an abnormal result comes back?
Is acting on a result within my scope of practice?
-ex. Sirolimus levels
-Yes if you are a transplant pharmacist
-No if you are a community pharmacist
Am I ready to be responsible for a critical value?

Question 25

Risks and Cost

Answer 25

• All labs pose a risk, benefit, and cost
• Some labs tests are invasive (penetrate skin/enter body)
• Must educate patients on both the RISKS and BENEFITS of the lab test before it is ordered
• Each lab test costs money to run; we should be cognizant of this to prevent wasted resources

Question 26

Special Instructions

Answer 26

• Some lab tests require special instructions before they are carried out (ex. fasting for at least 8 hrs)
• Inform patients what the lab test entails and what they should be doing to prepare
• Some lab tests are time-sensitive and require blood draws at a specific time (ex. drug levels)
• Some labs have special handling instructions (ex. on ice)

Question 27

Filling out the Requisition forms

Answer 27

• Requisition form specific to pharmacists
• Acquire all patient-specific information (ex. name, address, PHIN)
• Where the results are going: You need a copy to keep for record keeping, Primary care physician should get a copy
• Why are ordering the test - Make sure to have a good reason

Question 28

Flag Legend:

NR

Answer 28

outside normal range

Question 29

Flag Legend:

CR

Answer 29

outside critical range

Question 30

Flag Legend:

LL

Answer 30

linear range - low

Question 31

What are the 5 points for Interpreting Lab Values Systematic Approach

Answer 31

1) Compare result to the reference range
2) Consider patient-specific factors
3) Compare previous lab values
4) Is the abnormality clinically significant?
5) Does the abnormal value require management?