To evaluate whether a pregnant woman is in anemia or there exist the needs to replenish iron is usually based on the measurement of hemoglobin (HB) concentration, because the evaluation of iron nutritional status has not yet been used widely in our country. Blood specimens were collected from 258 pregnant women, and concentrations of Hb, serum ferritin (SF) and free erythrocyte protoporphyrin (FEP) were determined to find out a reasonably boundary value of Hb concentration from the two different ones set by our country and WHO, respectively, and the one averaged the former two, i.e, 100g/L, 110g/L and 105g/L. False positivity and false negativity in diagnosis of iron deficiency anemia (IDA) for pregnant women were evaluated based on the measurement of SF and FEP concentrations as gold standards. Results showed that the optimal Hb concentration for preliminary diagnosis of IDA was 105g/L with maximizing Yorden index.