In total 50 subjects with iron deficiency anemia treated with intravenous iron are planned for inclusion in this trial. After signing an informed consent a blood sample will be obtained from each participant before iron treatment. The investigators will measure the thrombin generation in plasma assessed by the calibrated automated thrombogram (CAT). patient will go face to face interview and will be asked to answer structured questionnaire which will include information on demographics, clinical data ( fever, allergies , etc.) and comorbidities

Two weeks after completing intravenous iron administration additional blood samples will be taken: thrombin generation will be measured

Inclusion Criteria:

• age >18 years
• Iron deficiency anemia that did not response to oral iron treatment and is planned to receive iron supplement intravenously.
• Signing the informed consent

exclusion criteria:

• chronic inflammatory disease
• renal failure
• Malignancy
• Infectious disease
• Other reason for anemia except iron deficiency anemia.
• Pregnant women
• Use of anti aggregating agents or anticoagulants

men and women over age 18 suffering from iron deficiency anemia that wasnt responded to oral iron treatment or there is contraindication for oral iron therapy.