A subcutaneous low molecular weight heparin injection is a widely accepted practice for the prophylaxis of deep venous thrombosis in postoperative patients that extends for 3 weeks after the surgery after discharge from the hospital. The nurse can go to the home of the patient to administer the heparin every day or the nurse can make a nursing assessment and if the result indicates "Insufficient knowledge" or "Fear", then a care plan can be devised to teach the patient or his or her patient to administer the shot.

Objective: To quantify the savings to the health care system of having the patient or his/her family administer the injection through nursing methodology. Methodology: Cost minimisation analysis. The total costs have been considered: the sum of direct and indirect costs. The costs per minute of the nursing professional as well as the time spent have been estimated.

Results: Cost per minute: 85.8 pesetas (0.52 cents). Cost of 3 weeks of home visits to administer the shot: between 12,613 pesetas (76.44 euros) and 55,856 pesetas (338.52 euros). Cost of the assessment, diagnosis and nursing treatment: between 4.033 pesetas (24.44 euros) and 10,210 pesetas (61.88 euros). Saving using nursing methodology: between 8,580 pesetas (52 euros) and 45,646 pesetas (276.64 euros) per person.

Conclusion: If a nursing methodology is applied during the course of outside hospital therapy of DVT prophylaxis , the cost is reduced between 52 and 276.64 euros per patient in our centre.