Goljan High Yield For Lab Medicine

Front 1

Definition:

positivity of a disease

1. positive predictive value
2. negative predictive value
3. sensitivity
4. specificity

Back 1

sensitivity

Front 2

Definition:

positivity of a disease

Definition

negativity in health

1. positive predictive value
2. negative predictive value
3. sensitivity
4. specificity

Back 2

specificity

Front 3

who is include a sensitivity test

(TP, FP, FN, TN)

Back 3

true positives and false negative

Front 4

what is the formula for sensitivity

Back 4

TP/ TP + FN

Front 5

when should a 100% sensitive test be used (3)

Back 5

1. screening for a disease

2. excludes disease when negative

3. includes pts when disease is positive

catch words includes and exclude

Front 6

what are the interpretation of a test with 100% sensitivity when it returns normal in a pt

Back 6

1. always has a negative predicitive value of 100% bc ( PV- TN/ TN +FN

2. it must be a N test result (excludes the disease) since there are not FN: a TN is a TN or normal

3. ex serum ANA has 100% sensitivity for SLE: a negative ANA excludes SLE

Front 7

what are the interpretation of a test with 100% sensitivity when it returns positive in a pt

Back 7

1. may be TP or FP (FP is a positive test result in a normal person)

2. people with the disease are always included

3. ex a positive serum ANA includes all people with SLE but does not confirm SLE since other diseases have positive ANA ( RA, systemic sclerosis)

Front 8

what does true negative mean

Back 8

normal test result in a person without the disease

Front 9

what does false positive mean

Back 9

the test is false bc said pt positively has the disease

Front 10

what is the formula for specificity

Back 10

TN/ TN + FP

Front 11

when do we use a 100% specific test

Back 11

to confirm a disease bc there are no FP test results so a positive must be a TP

Front 12

what are the interpretation of a test with 100% specificity when it returns positive in a pt

Back 12

1. confirms the disease in the pt

2. PPV is always 100% (PPV= TP/ TP +FP)

3. must be a TP since there are no FP

4. ex anti-SM for SLE is 100% specific so all pt with positive anti-Sm have SLE

Front 13

what are the interpretation of a test with 100% specificity when it returns negative in a pt

Back 13

1. may be TN or FN bc FN are not in the formula for specificity

2. it does not exclude the disease

3. ex if anti-Sm is neg in pt it does not mean that pt doesn't have SLE could have variant

Front 14

2 standard deviations covers how many of the population

Back 14

95%

Front 15

how do you calculate the reference interval of a test when given the mean of the test and 1 SD

Back 15

1. double the SD to include 95% of the population ( if the mean of the test is 100 and the SD is 5 then 2SDs is 10)

2. the reference interval is between 90 to 110 ( 100-10 is 90 and 100+10 is 110)

3 so for each test 5% of the pop will have test results outside of this reference interval

Front 16

SD is a marker of precision OR accuracy

Back 16

precision- reproducibility of the test, it is NOT a marker of accuracy

Front 17

T/F a test with the highest sensitivity increases the prevalence of the disease

Back 17

true- it picks up more people with the disease since it is a good screening test

Front 18

T/F a test with high specificity are good screening test bc they confirm the diease and help differential between TP and FP

Back 18

False- a test with high specificity are poor screening test bc they ONLY CONFIRM the diease and help differential between TP and FP

Front 19

what are the effects of increasing the upper limits of normal of a test reference interval on: sensitivity, specificity, PPV, NPV

Back 19

1. increases specificity and PPV

2. decreases sensitivity and NPV

Front 20

what are the effects of decreasing the upper limits of normal of a test reference interval on: sensitivity, specificity, PPV, NPV

Back 20

1. increases sensitivity and NPV

2. decreases specificity adn PPV

Front 21

what is the formula for prevalence

Back 21

P=I X D

Incidence ( new cases over a period of time)

Duration of disease

or TP + FN/ everything (TP.FN, FP, TN)

Front 22

as duration decreases what happens to prevalence

Back 22

decreases and vice versa, as duration increases prevalence increases

incidence is constant

Front 23

list 4 normal chages in pregnancy seen in lab values

Back 23

1. increase in plasma volume than RBC mass (decrease in Hb and Hct bc diluted) also GFR and creatinine increased since more plasma and decreased serum BUN again bc more plasma diluted

2. increase alkaline phosphatase (from placenta)

3. respiratory alkalosis- estrongen/progestorone effects on CNS center

4 increase T4 and cortisol

Front 24

what are the normal 2 main lab difference between men and women

Back 24

1. Fe studies are lower in women, serum Fe and ferritin

2. lower Hb in women

Front 25

list 3 normal difference in lab values of children vs adults

Back 25

1. increase serum alkaline phosphatase (osteroblast release enzyme when stimul bc vit d to increase bone minieralization)

2. increase serum phosphate ( to get Ca+ into bone)

3 decrease in Hb

Front 26

what are 3 effects of high HbF in newborns in lab values

Back 26

1. left shift of oxygen dissociation curve- causes tissue hypoxia

2. stimulates EPO

3. increase RBC production so will increase Hb

Front 27

list 4 protective features of HbF in newborn

Back 27

1. left shift of oxygen dissociation curve

2. protect newborn from sickle cell

3. protects from Beta-thalass

4. HbF synthesis is increases with hydroxyurea

5. HbF resistant to alkali/acid denturation

Front 28

which lipid component is most affected by fasting

Back 28

triglycerides- bc come from chylomicrons which are obtained from diet

Front 29

which 2 lipid components are not affected by fasting

Back 29

1. cholesterol CH

2. HDLs

Front 30

T/F fasting is necessary for an accurate LDL level

Back 30

true- LDL= CH -HDL - TG/5 so if TG are falsely increased by chylomicrons from the diet it will falsely lower the calculated LDL

Front 31

how does alcohol and barbiturate enhance the cytochome system in the liver SER

Back 31

1. induces SER hyperplasia

2. increase synthesis of gamma-glutamyltransferase (GGT)

3. decrease of drug levels owing to increase metabolism of drug

Front 32

T/F H2 blockers and proton pump blockers inhibit the cytochome system in the liver SER

Back 32

true- H2 blocker- cimetidine
omeprazole

Front 33

list 6 abnormal lab findings in alcholics

Back 33

1. inceased cytochrome p-450 ( increase GGT so good marker for alcholics)

2. increase NADH and its breakdown products (lactate, hypertriglyceridemai bc increase G3P which yeild TG)

3. increase ketoacids syntheiss

4. increase fatty acid synthesis

5. hyperuricemia

6. increase anion gap bc of lactate and beta-OHB

Front 34

what 5 abnormal lab test are found in smokers

Back 34

1. respiratory acidosis- air gets in but can't get out so CO2 stays in

2. hypoxemia- low PaO2

3. increase CO levels- CO from cigarettes

4. secondayr polycythemia- low PaO2 stimulate EPO

5. absolute neutrophilic leukocytosis- decreases leukocyte adhesion to endothelial

Front 35

which 2 lipoproteins carrry TGs

Back 35

chylomicrons- 85% and VLDL-55%

Front 36

how is Ca+2 transported in blood

Back 36

albumin-40%

47% free bc metabolically active

13% bound to other substances

Front 37

what is the effect of low albumin on calcium

Back 37

low serum albumin=low calcium bound of albumin so hypocalcemia but no tetany present since ionized levels are normal

Front 38

if 2 test are ordered on a pt, what are the chances of a FP result

Back 38

about 10%

Front 39

what is the effect of pregnancy on serum cortisol

Back 39

serum cortisol is increased due to increases in the binding protein and not the free hormone level