Optimized microturbidimetric assay for fibrinogen

Area of Science:

• Clinical Chemistry
• Biochemistry
• Hematology

Background:

• Accurate quantification of plasma fibrinogen is crucial for diagnosing and managing various hemostatic disorders.
• Existing methods for fibrinogen measurement can be susceptible to interference from various substances.
• Development of a robust and reliable fibrinogen assay is needed.

Purpose of the Study:

• To develop and validate a novel turbidimetric assay for plasma fibrinogen quantification.
• To assess the interference of common substances and monoclonal proteins on the assay's performance.
• To evaluate the assay's precision and correlation with established methods.

Main Methods:

• Plasma fibrinogen was precipitated using a reagent containing ammonium sulfate, EDTA, and guanidine hydrochloride.
• A two-step reagent addition and fixed reaction times were employed to minimize interference.
• The assay was calibrated with purified fibrinogen and validated against immunoturbidimetric, chronometric, and clotting assays.

Main Results:

• The assay demonstrated linear response from 0-10 g/L with within-run precision (CV) <2% from 1-10 g/L.
• Interference from bilirubin, hemoglobin, and chylomicrons was eliminated.
• Major interference from monoclonal proteins in adult samples was found to be very low (P = 0.0002).
• Extremely high correlations were observed with immunoturbidimetric (r=0.99), chronometric (r=0.99), and clotting (r=0.97) methods.

Conclusions:

• The developed turbidimetric assay provides a reliable, precise, and accurate method for plasma fibrinogen measurement.
• The assay is robust against common interfering substances and monoclonal proteins.
• This method offers a valuable alternative for routine clinical laboratory use in assessing fibrinogen levels.