Coagulation Profile
OVERVIEW
- Prothrombin Time
- Activated Partial Thromboplastin Time
- Thrombin Time
- Fibrinogen
- Fibrin Degradation Products (FDP’s)
- APTT 50% NP
- Retiplase Time
- Euglobin Lysis Time
- Urea solubility Test
PROTHROMBIN TIME
- thromboplastin added
- tests the extrinsic pathway
- ratio compared to control (INR)
- tests factors: I, II, V, VII, X
-> warfarin
-> vitamin K deficiency
-> liver disease
-> DIC
-> artefact: incorrect sampling or increased haematocrit (> 55%)
ACTIVATED PARTIAL THROMBOPLASTIN TIME
- kaolin added
- tests intrinsic pathway
- tests factors: I, II, V, VIII, IX, XI, XII
-> heparin
-> DIC
-> haemophilia
-> liver disease
THROMBIN TIME
- thrombin added to undiluted plasma
- tests the conversion of fibrinogen -> fibrin
- prolonged in:
-> heparin
-> DIC
-> hypofibrinogenaemia
-> fibrin degradation products
FIBRINOGEN
- normal: 1.5-4.0
- high in: acute phase response
- low in:
-> sepsis
-> DIC
FIBRIN DEGRADATION PRODUCTS (FDPs)
- marker of fibrin and fibrinogen breakdown
APTT 50% NP
- mixing of patients sample with pooled normal plasma – 50:50 mix
- failure to correct after mixing:
-> lupus anticoagulant present (should go on to autoantibodies and anti-cardiolipin antibodies)
ECHIS TIME
- snake venom from Echis multisquamatus added to sample
- differentiates liver dysfunction from vitamin deficiency
- this activates prothrombin without requiring vitamin K
- is normal in vitamin K deficiency or warfarin use
- if prolonged:
-> factor deficiency (liver disease)
RETIPLASE TIME
- used to detect deficiency or abnormalities in fibrinogen
- snake venom that has similar action to thrombin but is resistant to inhibition by antithrombin III
- interpret with TCT
- if retiplase time normal and TCT prolonged:
-> heparin
-> hirudin
-> direct thrombin inhibitors
EUGLOBIN LYSIS TIME
- shortened time:
-> presence of systemic fibrinolytic pathway activators
UREA SOLUBILITY TEST
- factor 13 stabilises fibrin
- if deficient 5M urea will dissolve it
References and Links
CCC Transfusion Series
Blood Products: Cryoprecipitate, Fresh Frozen Plasma (FFP), Platelets, Red Cells (RBCs)
>>> Factor Concentrates: Prothrombinex, Factor VIIa, Fibrinogen Concentrate
Reversal Agents:
>>> Rivaroxaban / Apixaban / Enoxaparin: Andexanet Alfa, Rivaroxaban and Bleeding
>>> Dabigatran: Idarucuzimab, Dabigatran and bleeding
>>> Heparin: Protamine
>>> Warfarin: Vitamin K, FFP, PTx, Warfarin Refersal, Warfarin Toxicity
Testing: Coagulation Studies, TEG / ROTEM (Thromboelastography), Platelet function assays
Conditions: Acute Coagulopathy of Trauma, Disseminated Intravascular Coagulation (DIC), Massive Blood Loss
General Topics: Blood Bank, Blood Conservation Strategies, Blood Product Compatibilities, Blood Transfusion Risks, Massive Transfusion Protocol (MTP), Modifications to Blood Components, Procedures and Coagulopathy, Storage Lesions, TRALI, Transfusion Literature, Transfusion Reactions
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Critical Care
Compendium
Chris is an Intensivist and ECMO specialist at The Alfred ICU, where he is Deputy Director (Education). He is a Clinical Adjunct Associate Professor at Monash University, the Lead for the Clinician Educator Incubator programme, and a CICM First Part Examiner.
He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives. He was one of the founders of the FOAM movement (Free Open-Access Medical education) has been recognised for his contributions to education with awards from ANZICS, ANZAHPE, and ACEM.
His one great achievement is being the father of three amazing children.
On Bluesky, he is @precordialthump.bsky.social and on the site that Elon has screwed up, he is @precordialthump.
| INTENSIVE | RAGE | Resuscitology | SMACC