Overview: Vitamin K TestIntroduction: The Vitamin K Test measures vitamin K to diagnose deficiency, causing excessive bleeding. Following 2023 ASH guidelines, it uses biochemical methods for high specificity, supporting coagulation screening. This test is critical for guiding diagnosis, treatment planning, and improving outcomes in biochemistry for patients with suspected vitamin K deficiency.
Other Names: Vitamin K Assay, Phylloquinone Test.
FDA Status: Laboratory-developed test (LDT), meeting biochemistry standards for diagnostic accuracy.
Historical Milestone: Vitamin K testing began in the 1960s with coagulation research. Biochemical methods improved in the 2000s, enhancing diagnostic precision.
Purpose: Measures vitamin K to diagnose deficiency, guides treatment, and evaluates patients with excessive bleeding.
Test Parameters: 1. Vitamin K Level
Pretest Condition: Fasting for 10-12 hours required. Collect serum or plasma. Report history of bleeding or nutritional deficiencies.
Specimen: Serum (SST, 2-5 mL), Plasma (EDTA, 2-4 mL). Transport in a biohazard container.
Sample Stability at Room Temperature: 8 hours
Sample Stability at Refrigeration: 7 days
Sample Stability at Frozen: 6 months
Medical History: Document excessive bleeding, bruising, or history of nutritional deficiencies. Include current medications, especially anticoagulants.
Consent: Written consent required, detailing the tests purpose, vitamin K deficiency implications, and risks of sample collection.
Procedural Considerations: Uses high-performance liquid chromatography (HPLC) to measure vitamin K levels. Results are available in 1-2 days, supporting clinical decisions. Performed in laboratories, often for coagulation disorder diagnosis.
Factors Affecting Result Accuracy: Improper fasting or sample hemolysis can affect results. Anticoagulants like warfarin may reduce levels.
Clinical Significance: Low vitamin K confirms deficiency, guiding supplementation or anticoagulant reversal. Normal levels may require coagulation factor testing.
Specialist Consultation: Consult a hematologist for result interpretation and treatment planning.
Additional Supporting Tests: Prothrombin time, INR, or coagulation factor assays to confirm vitamin K deficiency diagnosis.
Test Limitations: Non-specific for deficiency cause; clinical correlation is needed. Sample quality affects sensitivity.
References: ASH Hematology Guidelines, 2023; Blood, Shearer MJ, 2022.
