Intro

Question 1

Goal of labs

Answer 1

narrow down the differential diagnosis, monitor disease, evaluate treatment response

Question 2

Screening test

Answer 2

the patient does NOT have signs or symptoms

good test: high sensitivity
-Few false negatives

Question 3

sensitivity

Answer 3

probability patient with a disease will have a positive test

(N in sensitivity does NOT go with negative)

Question 4

Diagnostic test

Answer 4

patient has signs or symptoms

good test: high specificity
-few false positives

Question 5

Specificity

Answer 5

probability a healthy patient will have a negative test

Question 6

what is blood broken up into and place in order lease dense to most dense

Answer 6

plasma -> WBC & platelets (buffy coat) -> RBC

serum (unclotted- plasma) -> clotted blood (RBC, WBC, Platelets)

Question 7

what is plasma made of

Answer 7

unclotted blood, without cellular elements

Question 8

when can Serum ONLY be collected

Answer 8

in a tube without anticoagulant

Question 9

what is an analyte

Answer 9

substance measured by an assay

can be protein-bound or free (active from)

Question 10

What are 3 types of tests

Answer 10

qualitative, quantitative, or semi-quantitative (reported as negative or varying degree of positivity, 1+, 2+, ect…)

(there is NOT a semi-qualitative test)

Question 11

what is accuracy vs precision

Answer 11

accuracy: value is close to the true value (center of the target)
precision: repeated trials all give the same value (multiple values at same are of target)

Question 12

Deci

Answer 12

10-1 (d)

Question 13

Centi

Answer 13

10-2 (c)

Question 14

Mili

Answer 14

10-3 (m)

Question 15

Micro

Answer 15

10-6 (u)

Question 16

Nano

Answer 16

10-9 (n)

Question 17

Pico

Answer 17

10-12 (p)

Question 18

Femto

Answer 18

10-15 (f)

Question 19

what is the purpose of titers

Answer 19

to detect the presence and amount of a substance in a serum

value expressed as highest dilution where a positive test result present

(use and ELISA test for antibody titers)

Question 20

are all healthy people’s lab values within the reference range

Answer 20

No, 5% of healthy people will still be outside of normal range (outside of -/+ 2 SD)

Question 21

how should panic values be delivered

Answer 21

by phone call immedialty

Question 22

what rate of change in results raises alert/ require urgent response

Answer 22

if there is a rapid change in results

Question 23

what is point of care testing

Answer 23

where sample is taken and test is run and evaluated in the same room (ex: finger pricked then tested in the office)

Question 24

centralized laboratory tests

Answer 24

these tests require more complex equipment; samples taken then sent off to another room or lab for testing

requires regulation: CLIA

Question 25

Positive Predictive value

Answer 25

probability that a person with a positive test will have the disease

Based on test

(compare the test result to the person having disease or not, unlike sensitivity and specificity where compare the disease state of person to test result)

Question 26

Negative Predictive Value

Answer 26

Probability that a person with a negative test will not have the disease (determine if a person is healthy)

Question 27

Which 2 of the 4 are influnced by prevalence of a disease?

Positive predictive value, negative predictive value, sensitivity and specificity

Answer 27

Positive and negative predictive value

Question 28

likelihood ratio is based on?

what are the 4 tests with in it

Answer 28

sensitivity and specificity

Pre-test probability: presence of disease before test
Post-test probability: presence of disease after test
Positive Likelihood value: (sensitivity)/(1-specificity)
=(% disease with + test)/(% healthy with + test)
Negative Likelihood value: (1-sensitivity)/(specificity)
=(% diseased with - test)/(% healthy with - test)