POC: INR

Question 1

T or F: Lab testing INR uses capillary blood samples

Answer 1

F- uses venous blood

Question 2

What are the main negatives of lab INR testing

Answer 2

takes so long
— delay in results
- get puncture done (appointment); send sample to lab (may. be different location); takes like 24 hours to get results to MD —- must communicate + call pt

Question 3

What can impact INR

Answer 3

non-adherence
drugs/supplements
changes in health status
changes in activity
stress
diet
alcohol
smoking

Question 4

What are the 2 POC INR tests available in Canada

Answer 4

CoagucheK XS: Nagge ‘s lab uses this one because more studied + has a quality assurance program (every 4 mths - company sends standard sample to be run through machine to ensure still functioning well)

CoagucheK XS PRO:

Question 5

How is PT measured

Answer 5

take venous blood, centrifuge to remove cells, use citrate to remove Ca

— take decalcifeid plasma + TF +Ca —- time to clot (PT)

** a lot of variation due to different TF used; INR standardizes results

Question 6

Similarities bw lab INR + POC INR

Answer 6

both use thromboplastin reagent + measure time to complete extrinsic pathway

Question 7

What is different in POC INR testing compared to lab

Answer 7

• use capillary blood
• endpoint measured is the conversion of thrombin substrate (OTHER THAN Fibrinogen)
  —— doesn’t directly measure time to clot (fibrinogen to fibrin conversion)

Question 8

What reaction does POC INR tests measure

Answer 8

measures production of electro active compound
—— thrombin cleaves amide bond from a target substrate at carbohydrate terminus of arginine residue

** measures production of electrochemically inert compound

Question 9

T or F: greatest differences seen in POC test vs INR labs are when INR values are higher

Answer 9

T— if INR> 3.5 ; greatest differences seen bw POC + lab INR results (differences)

—— normally POC devices are good (differences rarely clinically significant)

Question 10

Impact of POC INR tests on TTR vs when use lab tests

Answer 10

people using POC meter spend more time in therapeutic range in comparison to lab

— no differences in bleed risk etc

— gernally have more satisfaction + improved QoL

Question 11

What is the biggest barrier to POC INR testing

Answer 11

Cost + lack of coverage

Question 12

What are the benefits of POC INR

Answer 12

allows for pharmacist to be responsible for lab results

allows collaboration with different HCP

allows for management of extreme INR right away

Allows pt to self test (ex// travelling

** improvement anticoag management, improvement in quality measures (TTR, QoL)