NIRS measurements of hemoglobin and hemoglobin saturation in tissues before and after red-cell transfusions in VLBW infants will determine the true effect of the transfusions, and develop more substantial guidelines regarding indications for transfusion. The accuracy of conventional (invasive) measurements of Hb and Hct could be comparison with results from the NIRS technique and clinical usefulness of the NIRS technique could be evaluated by comparison with trends in conventionally measured values taking fluid status into account.