Fibrinogen plays a vital role in normal homeostasis by promoting platelet aggregation, clot formation and fibrinolysis. It is quantified in finished pharmaceutical products using different methods described in pharmacopoeia, but these are inaccurate, difficult to validate and do not allow for identification of aggregates or protein products of the same formulation. The aim of this study was to develop and validate a method for quantification of the content of fibrinogen and other proteins present in pharmaceutical formulations by comparing it with current pharmacopeial methods. Fibrinogen was quantified in two commercial products and compared to a pharmacopeial method using a validated method for size-exclusion high-pressure liquid chromatography (SEC-HPLC). The fibrinogen level was in accordance with both products’ specifications. The SEC-HPLC method showed that the percentage of fibrinogen was 94.88 for one product and 50.68 for the other, and detected high molecular weight aggregates in the second product. The SEC-HPLC method that we developed is an improvement to the current pharmacopeial method, because it allows for quantification of fibrinogen and determination of product purity. This is important because greater purity can reduce potential adverse effects of pharmaceutical products in patients.