Coagulation - Revision history

Admin: /* Coagulation Testing */

2025-02-01T21:11:04Z

Coagulation Testing

← Older revision		Revision as of 17:11, 1 February 2025
Line 248:		Line 248:
	'* FEU or DEU may be used for measurement		'* FEU or DEU may be used for measurement

	*		== Anticoagulant Drugs ==
			{\| class="wikitable"
			\|+
			!Drug
			!Mechanism of Action
			!Monitoring
			!Reversal
			\|-
			\|Unfractionated Heparin (UFH)
			\|INDIRECT

			* Various length chains of glycosaminoglycans
			* Combines with antithrombin (as pentasaccharide)
			* Inhibits IIa, Xa, IXa, XIa, and XIIa
			\|
			* APTT
			* Anti-Xa assay
			\|Elective

			* Discontinue IV for 4 hoursEmergency

			* Protamine sulfate
			\|-
			\|Low Molecular Weight Heparin (LMWH)

			* Dalteparin, enoxaparin, nadroparin, tinzaparin, etc.
			\|INDIRECT

			* Smaller chains of heparin (fractionated out)
			* Combine with antithrombin (pentasaccharide)
			* Inhibits Xa and IIa only
			* Relative inhibition of factors (Xa:IIa ratio) various by formulation
			\|Not usually required

			* Anti-Xa assay only
			\|Elective

			* 12-24 hours discontinuation

			Emergency

			* Andexanet alpha pending approval
			* Protamine may reverse effects on IIa only for intravascular LMWH
			\|-
			\|Warfarin (Coumadin)
			\|
			* Vitamin K antagonist
			* Prevents activation of vitamin K-dependent factors
			** II, VII, IX, X, anticoagulant proteins
			\|
			* PT/INR
			\|Elective

			* 5 days discontinuation (bridging may be done for some patients)
			* Vitamin K if non-urgent

			Emergency

			* Vitamin K - activates factors already present
			* Prothrombin complex concentrates (PCCs - Octaplex)
			** Contain Vitamin K-dependent factors and some heparin
			** Contraindicated in HIT
			\|-
			\|Fondaparinux
			\|INDIRECT

			* Synthetic pentasaccharide
			* Combines with antithrombin
			* Inhibits FXa only
			\|Not usually required

			* Anti-Xa assay only
			\|Elective

			* 1-2 days discontinuation

			Emergency

			* Andexanet alpha (pending approval) may be helpful
			* Otherwise, none
			\|-
			\|Direct Thrombin Inhibitors (DTIs)

			* Dabigatran (VTE, stroke prevention)
			* Argatroban, Bivalirudin, Lepirudin (HIT treatment)
			\|DIRECT

			* Synthetic
			* Directly inhibit thrombin, do not require antithrombin (direct-acting)
			\|Not usually required
			\|Elective varies
			Emergency (dabigatran)

			* Idarucizumab
			* Activated charcoal (within 2 hours)
			* Hydration
			\|-
			\|Direct Xa Inhibitors

			* Rivaroxaban
			* Apixaban
			* Edoxaban
			\|
			* Synthetic
			* Directly inhibit FXa (don't require antithrombin)
			* Used for prevention of VTE and stroke
			\|Not usually required

			* Anti-Xa assay only
			\|Elective varies
			Emergency

			* Andexanet alpha (pending approval)
			* Prothrombin complex concentrates (PCCs - Octaplex)
			\|}

Admin: /* Coagulation Testing */

2025-02-01T20:46:39Z

Coagulation Testing

@@ Line 144: / Line 144: @@
 !Why?
 !How? (Methodology)
-!Causes of Abnormal Results
+!Associated Conditions
 !RI
 |-
@@ Line 175: / Line 175: @@
 * Run thrombin time (high thrombin concentration) and plot results of concentration vs. time
 * Patient samples can then be run and compared to the curve to determine fibrinogen concentration
+* Clot time inversely proportional to fibrinogen activity
 |1.5 - 4 g/L
 |-
@@ Line 191: / Line 203: @@
 * Acquired fibrinogen deficiencies
 * Increased clot breakdown (e.g., DIC)
+|
 |-
 |Unfractionated Heparin/Anti-Xa Assay
+|
+* Known value of Factor Xa is added in excess to patient sample
+* Complex formed between drug and coagulation factor
+* Unbound FXa hydrolyzed and abosrbance measured
 |-
 |Factor Assays
@@ Line 205: / Line 246: @@
+|
 |}

Admin at 20:22, 1 February 2025

2025-02-01T20:22:29Z

← Older revision		Revision as of 16:22, 1 February 2025
Line 133:		Line 133:
	300ul citrate		300ul citrate

	Coagulation Testing		== Coagulation Testing ==
			All coagulation testing uses sodium citrate (light blue top) tubes to yield plasma. Centrifuge to separate plasma from platelets, yielding platelet poor plasma (to prevent activation of coagulation).

			* RT: 4 hours
			* Frozen: 2 weeks (-20C) to 6 months (-80C)

	{\| class="wikitable"		{\| class="wikitable"
	\|+		\|+
	!Test		!What? (Test)
	!~~Test Method~~		!Why?
			!How? (Methodology)
	!Causes of Abnormal Results		!Causes of Abnormal Results
	!RI		!RI
	\|-		\|-
	\|PT/INR (Prothrombin Time)		\|PT/INR (Prothrombin Time)
			\|Assess deficiencies or inhibitors of '''extrinsic or common''' pathways
	\|		\|
	* ~~Citrated PPP~~ (~~platelet poor plasma~~)		* Calcium thromboplastin added to sample (calcium and tissue factor source)
	* ~~Calcium thromboplastin added~~		** Activates coagulation cascade
	* Measured optically or mechanically		* Measured optically or mechanically
	** Optical: light scattered as fibrin strands form		** Optical: light scattered as fibrin strands form
	** Mechanical: magnetic balls oscillates, movement impeded by clot		** Mechanical: magnetic balls oscillates, movement impeded by clot
	\|		\|
	\|11.5-13.5s		\|11.5 - 13.5 s
	INR: 0.9-1.2		INR: 0.9 - 1.2
	\|-		\|-
	\|APTT		\|APTT
			\|Assess deficiencies or inhibitors of '''intrinsic or common''' pathways
	\|		\|
	* ~~Citrated PPP mixed with~~ APTT reagent		* APTT reagent added to sample (contains contact activator and phospholipids)
	* Activation of factor XII and XI		** Activation of factor XII and XI
	* Calcium then added to activate factor IX and VIII		* Calcium then added to activate factor IX and VIII
	* Factor X activated, causing cascade to activate Factor II and I, forming fibrin clot		* Factor X activated, causing cascade to activate Factor II and I, forming fibrin clot
	\|		\|
	\|23-35 s		\|23 - 35 s
	\|-		\|-
	\|Fibrinogen (Clauss Assay)		\|Fibrinogen (Clauss Assay)
			\|Assess fibrinogen activity
	\|		\|
	* Clauss assay uses reference plasma samples with known concentrations of fibrinogen		* Clauss assay uses reference plasma samples with known concentrations of fibrinogen
Line 167:		Line 176:
	* Patient samples can then be run and compared to the curve to determine fibrinogen concentration		* Patient samples can then be run and compared to the curve to determine fibrinogen concentration
	\|		\|
	\|		\|1.5 - 4 g/L
	\|-		\|-
	\|Thrombin Time		\|Thrombin Time
			\|Assess deficiencies of fibrinogen or the presence of thrombin inhibitors
	\|		\|
	* Citrated PPP		* Low concentration of thrombin added to cleave fibrinogen → fibrin
	* Low concentration of thrombin added to cleave fibrinogen -> fibrin
	* Measure time to form fibrin clot		* Measure time to form fibrin clot
	\|		\|Drugs
	* ~~Congential~~ fibrinogen deficiencies		* Heparin
	* Acquired fibrinogen ~~deficincies~~		* Direct thrombin inhibitors (dabigatran, apixaban, etc.)
	* ~~Unfractionated heparin~~		Conditions
	* Direct thrombin inhibitors (~~dabigatran~~, ~~apixaban~~)
			*Congenital fibrinogen deficiencies
			* Acquired fibrinogen deficiencies
			* Increased clot breakdown (e.g., DIC)
	\|		\|
	\|-		\|-
	\|Unfractionated Heparin/Anti-Xa Assay		\|Unfractionated Heparin/Anti-Xa Assay
			\|
	\|		\|
	\|		\|
Line 187:		Line 200:
	\|-		\|-
	\|Factor Assays		\|Factor Assays
			\|
	\|		\|
	\|		\|
	\|		\|
	\|}		\|}

Admin at 22:39, 27 January 2025

2025-01-27T22:39:14Z

← Older revision		Revision as of 18:39, 27 January 2025
Line 132:		Line 132:

	300ul citrate		300ul citrate

			Coagulation Testing
			{\| class="wikitable"
			\|+
			!Test
			!Test Method
			!Causes of Abnormal Results
			!RI
			\|-
			\|PT/INR (Prothrombin Time)
			\|
			* Citrated PPP (platelet poor plasma)
			* Calcium thromboplastin added
			* Measured optically or mechanically
			** Optical: light scattered as fibrin strands form
			** Mechanical: magnetic balls oscillates, movement impeded by clot
			\|
			\|11.5-13.5s
			INR: 0.9-1.2
			\|-
			\|APTT
			\|
			* Citrated PPP mixed with APTT reagent
			* Activation of factor XII and XI
			* Calcium then added to activate factor IX and VIII
			* Factor X activated, causing cascade to activate Factor II and I, forming fibrin clot
			\|
			\|23-35 s
			\|-
			\|Fibrinogen (Clauss Assay)
			\|
			* Clauss assay uses reference plasma samples with known concentrations of fibrinogen
			* Run thrombin time (high thrombin concentration) and plot results of concentration vs. time
			* Patient samples can then be run and compared to the curve to determine fibrinogen concentration
			\|
			\|
			\|-
			\|Thrombin Time
			\|
			* Citrated PPP
			* Low concentration of thrombin added to cleave fibrinogen -> fibrin
			* Measure time to form fibrin clot
			\|
			* Congential fibrinogen deficiencies
			* Acquired fibrinogen deficincies
			* Unfractionated heparin
			* Direct thrombin inhibitors (dabigatran, apixaban)
			\|
			\|-
			\|Unfractionated Heparin/Anti-Xa Assay
			\|
			\|
			\|
			\|-
			\|Factor Assays
			\|
			\|
			\|
			\|}

Admin at 18:02, 22 January 2025

2025-01-22T18:02:32Z

← Older revision		Revision as of 14:02, 22 January 2025
Line 19:		Line 19:
	\|I		\|I
	\|Fibrinogen		\|Fibrinogen
	\|		\|Common
	\|		\|
	\|		\|
Line 25:		Line 25:
	\|II		\|II
	\|Prothrombin		\|Prothrombin
	\|		\|Common
	\|		\|
	\|		\|
Line 43:		Line 43:
	\|V		\|V
	\|Labile factor		\|Labile factor
	\|		\|Common
	\|		\|
	\|		\|
Line 49:		Line 49:
	\|VII		\|VII
	\|Stable factor		\|Stable factor
	\|		\|Extrinsic
	\|		\|
	\|		\|
Line 55:		Line 55:
	\|VIII		\|VIII
	\|Anti-hemophilic factor		\|Anti-hemophilic factor
	\|		\|Intrinsic
	\|		\|
	\|		\|
Line 61:		Line 61:
	\|IX		\|IX
	\|Christmas Factor		\|Christmas Factor
	\|		\|Intrinsic
	\|		\|
	\|		\|
Line 67:		Line 67:
	\|X		\|X
	\|Stuart-Prower Factor		\|Stuart-Prower Factor
	\|		\|Common
	\|		\|
	\|		\|
Line 73:		Line 73:
	\|XI		\|XI
	\|PTA (Plasma Thromboplastin Antecedent)		\|PTA (Plasma Thromboplastin Antecedent)
	\|		\|Intrinsic
	\|		\|
	\|		\|
Line 79:		Line 79:
	\|XII		\|XII
	\|Hageman Factor		\|Hageman Factor
	\|		\|Intrinsic
	\|		\|
	\|		\|
Line 86:		Line 86:
	\|Fibrin Stabilizing Factor (FSF)		\|Fibrin Stabilizing Factor (FSF)
	\|		\|
			\|Crosslinks adjacent fibrin strand D-domains to make an insoluble polymer
	\|		\|
	~~\|Crosslinks adjacent fibrin strand D-domains to make an insoluble polymer~~
	\|-		\|-
	\|VWF		\|VWF
Line 96:		Line 96:
	\|-		\|-
	\|HMWK		\|HMWK
	\|		\|High Molecular Weight
	\|		\|
	\|		\|
Line 107:		Line 107:
	\|		\|
	\|}		\|}
			Stages of Hemostasis

			# Primary hemostasis
			# Secondary hemostasis
			# Fibrin clot formation
			# Coagulation inhibition

	Protein Z		Protein Z

Admin: 1 revision imported

2024-02-20T16:12:16Z

1 revision imported

← Older revision	Revision as of 12:12, 20 February 2024
(No difference)

MedLabWIki>Admin at 12:49, 25 April 2023

2023-04-25T12:49:23Z

New page

Factors II, V, VIII, HMWK -> cofactors

Factors II, VII, 9-12, Prekallikrein -> serine proteases

Vitamin K Dependent Factors

* Serine Proteases
** Factors II, VII, IX, X
** Regulatory control proteins C, S, Z

{| class="wikitable"
|+
!Factor
!Other Names
!Pathway(s)
!Role
!Location of Synthesis
|-
|I
|Fibrinogen
|
|
|
|-
|II
|Prothrombin
|
|
|
|-
|III
|Tissue Factor (TF)
|
|
|
|-
|IV
|Ca2+
|
|
|
|-
|V
|Labile factor
|
|
|
|-
|VII
|Stable factor
|
|
|
|-
|VIII
|Anti-hemophilic factor
|
|
|
|-
|IX
|Christmas Factor
|
|
|
|-
|X
|Stuart-Prower Factor
|
|
|
|-
|XI
|PTA (Plasma Thromboplastin Antecedent)
|
|
|
|-
|XII
|Hageman Factor
|
|
|
|-
|XIII
|Fibrin Stabilizing Factor (FSF)
|
|
|Crosslinks adjacent fibrin strand D-domains to make an insoluble polymer
|-
|VWF
|
|
|
|
|-
|HMWK
|
|
|
|
|-
|
|
|
|
|
|}
Protein Z

* Z-dependent protease inhibitor (ZPI)
* Protein Z enhances ZPI activity
** inhibits factor X and XI

Restoring Blood Flow

* Fibrinolytic proteins
** Plasminogen
*** Converted into plasmin by TPA and UPA
*** Plasmin helps restore blood flow
** TPA
** UPA

1.85*10^-3 x (100-HCT) x v

300ul citrate