All of the following are the primary vitamin K-dependent clotting factors produced by the liver, EXCEPT:

Appeared in: BTSC Staff Nurse 1 August-2025

Explanation

Factor XI is the correct choice because its synthesis by the liver does not depend on Vitamin K.
The primary Vitamin K-dependent clotting factors are II, VII, IX, and X, along with anticoagulant proteins C and S.
Vitamin K acts as a cofactor for the enzyme gamma-glutamyl carboxylase, which adds a carboxyl group to glutamate residues on these factors.
Factor XI is part of the intrinsic pathway of the coagulation cascade but is not a 'Gla-containing protein' like the Vitamin K-dependent factors.

Option A: Factor II (Prothrombin) is incorrect because it is a primary Vitamin K-dependent clotting factor. It is the precursor to thrombin, a central enzyme in coagulation.
Option B: Factor VII (Proconvertin) is incorrect because its synthesis is dependent on Vitamin K. It plays a crucial role in initiating the extrinsic pathway of coagulation.
Option C: Factor X (Stuart-Prower factor) is incorrect as it is a Vitamin K-dependent factor. It is a key protein where the intrinsic and extrinsic pathways converge to form the common pathway.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Vitamin K-dependent clotting factors as background academic context rather than a clinical decision trigger.
Understanding Vitamin K-dependent factors is crucial for nurses managing patients on anticoagulants like warfarin (Coumadin), which works by inhibiting Vitamin K, thereby reducing the synthesis of these factors to prevent clots.
Nurses must monitor the Prothrombin Time (PT) and International Normalized Ratio (INR) for patients on warfarin to ensure therapeutic anticoagulation and prevent bleeding or clotting complications.
What if? If a patient on warfarin has a critically high INR and is actively bleeding, the nurse would anticipate orders to administer Vitamin K (phytonadione) as an antidote to reverse the anticoagulant effect.

How to Approach the Question

First, identify the core concept of the question, which is the group of 'Vitamin K-dependent clotting factors'.
Recognize the keyword 'EXCEPT'. This signals that you must find the option that does NOT fit into this group.
Recall the specific factors that are Vitamin K-dependent. A common mnemonic is '1972' for factors 10 (X), 9 (IX), 7 (VII), and 2 (II).
Evaluate each option against this known group:
Factor II is in the group.
Factor VII is in the group.

Concept Tested & Keywords

Concept Tested: Vitamin K-dependent clotting factors
Stem keywords: vitamin K-dependent, clotting factors, liver
Lead-in keywords: EXCEPT
Negative lead-in flag: The question asks for the exception among the given options.

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Practise the full BTSC Staff Nurse 1 August-2025

Attempt every question from this paper in a timed mock, then review the full solution for each one.