Ch 11 - Laboratory Values - Coagulation Studies

Front 1

aPTT

Back 1

- activated partial thromboplastin time

- evaluates HOW WELL the coagulation sequence (intrinsic clotting system) is functioning by measuring; amount of time in secs for plasma to clot after partial thromboplastin is added to it

Front 2

aPTT is test for?

Back 2

- test screens for deficiencies and inhibitors of all factors, except for factors VII and XIII

- used to monitor the effectiveness of heparin therapy and screen coagulation disorders

Front 3

aPTT value is?

Back 3

20 to 30 secs

Front 4

aPTT RN consideration

Back 4

- client receiving intermittent heparin ; draw blood sample 1hr before the next schedule dose

- do not draw sample from an arm into which heparin is infusing

- direct pressure to the venipuncture site for 3-5 mins

- aPTT should be bet. 1.5 and 2.5 times normal when client is receiving heparin therapy

Front 5

aPTT to remember

Back 5

- if the aPTT value is prolonged ( longer than 90 secs) in client receiving IV heparin therapy, initiate bleeding precautions

Front 6

PT

INR

Back 6

- Prothrombin time

- international normalized ratio

- Vitamin K-dependent glycoprotein produced by the liver that is necessary for fibrin clot formation

- measures the amount it takes in secs for clot formation

- used to monitor response to warfarin sodium ( Coumadin ) therapy

- to screen for dysfunction of the extrinsic clotting system resulting from liver disease, vit K deficiency or disseminated intravascular coagulation

- frequently used to measure the effects of oral anticoagulants

Front 7

PT values

Back 7

- a PT value within 2 seconds (plus or minus) of the control is considered normally

- PT= 9.6 -11.8 secs ( male adult)

9.5 - 11.3 secs (female adult)

- INR = 2 - 3 secs for standard

warfarin therapy

- INR = 3 - 4.5 secs for high-dose

warfarin therapy

Front 8

PT RN consideration

Back 8

- if PT is prescribed, baseline data should be drawn before anticoagulation therapy is started; note the time of collection in the lab. form

- direct pressure on the venipuncture site for 3 - 5 mins

- concurrent warfarin therapy with heparin therapy can lengthen the PT for up to 5 hrs after dosing

- diet with green leafy vegetables helps increase absorption of vit K, result in shorten PT

- Oral anticoagulant therapy the PT is at 1.5 - 2 times the lab values

Front 9

PT to remember

Back 9

- PT value of longer than 30 secs, receiving warfarin therapy must initiate bleeding precautions

Front 10

Platelet Count

Back 10

- Fx in hemostatic plug formation, clot retraction and coagulation factor activation

- Produce by the bone marrow

Front 11

Platelet count value?

Back 11

150,000 - 400,000 cells/mm3

Front 12

Platelet RN consideration

Back 12

- monitor venipuncture site for bleeding with known thrombocytopenia

- increase in high altitudes, chronic cold weather and exercise

- bleeding precaution for clients with low platelet count

Front 13

Platelet count to consider

Back 13

- monitor platelet count closely when receiving chemotherapy; risk for thrombocytopenia

Front 14

Bleeding time

Back 14

- is to assess hemostatic function ( platelet response to injury and vasoconstrictive ability )

- usefull in detecting platelet disorders

Front 15

Bleeding time RN consideration

Back 15

- validate client whos receiving anticoagulant, aspirin for 3 days prior to test

Front 16

D-dimer test

Back 16

- measures clot formation and lysis that results from the degradation of fibrin

- helps to dx presence of thrombin, pulmonary embolism, stroke, DIC ( dissiminated Intravascular Coagulation ) and monitor effectivness of tx