Lab tests

Question 1

def. bayes theorem

Answer 1

clinical utility of a test is best when pre-test prob is intermediate

Question 2

5 tests for SLE

Answer 2

1. ANA
2. anti dsDNA
3. ENA
4. serum complements
5. antiphospholipid AB

Question 3

def. ANA

Answer 3

ABs that react with nuclear antigens

Question 4

sens and spec of ANA for SLE

Answer 4

sens - 95-100

spec - not very

Question 5

implications of this

Answer 5

if have no ANA - not SLE

but if have, it can be something else

Question 6

implications of staining patterns

Answer 6

not very helpful

Question 7

what can be helpful with ANA

Answer 7

very high concentrations can be correlated

Question 8

Sens and spec of dsDNA

Answer 8

sens - medium for SLE

spec - very high

Question 9

what else if dsDNA good for

Answer 9

can be good for following disease if they are concordant

Question 10

what is tested for in complement

Answer 10

tends to be used up and go down in SLE

Question 11

what is RF

Answer 11

AB that binds to Fc of other ABs

Question 12

sens and spec of RF

Answer 12

sens - medium
spec - poor
- not a great test

Question 13

when is testing for RF most useful

Answer 13

when already have moderate probability based of hist

Question 14

what is anti CCP

Answer 14

AB against AA formed from arginine

- useful in RA

Question 15

sens and spec of antiCCP

Answer 15

sens - medium

spec - good

Question 16

what is anti CCP takehome

Answer 16

• detectable in early disease
• more spec. than RF
• not useful in measuring other disease

Question 17

what is acute phase response

Answer 17

• within hours of inflamm
• early def. mech
• major inducers IL1,6, TNF

Question 18

when is acute phase response

Answer 18

• infection
• inflammation
• neoplastic
• trauma

Question 19

2 acute phase reactant tests

Answer 19

1. ESR

2. CRP

Question 20

disadv. of ESR

Answer 20

• affected by age and gender
• affected by RBC morpp
• many plasma proteins
• requires fresh sample

Question 21

disadv. of CRP

Answer 21

$$

Question 22

take home for acute phase reactants

Answer 22

• little diagnositc value
• too sens
• not specific
• may be useful for following disease

Question 23

what is use of creat. and urinanalysis

Answer 23

physical exam of the kidney