Determination of the serum ferritin concentration is the only commonly used laboratory test that allows the evaluation of iron reserves. A serum ferritin concentration of less than 10 mg/liter in infants and children and less than 12 µg/liter in adults by itself indicates depleted iron stores. In combination with low hemoglobin or hematocrit levels, a serum ferritin concentration of less than 15 µg/liter in infants and children or less than 20 µg/liter in adults indicates iron deficiency anemia (LSRO, 1984). The serum ferritin concentration is elevated in the presence of infection and should be measured when the person is free of infectious disease (i.e., for at least 2 weeks).

Erythrocyte protoporphyrin accumulates in red blood cells when insufficient iron is available to form heme, the iron-containing portion of hemoglobin. Erythrocyte protoporphyrin levels are elevated in individuals with iron deficiency anemia or lead poisoning, as well as in those with infections or inflammatory conditions of more than 1 week in duration. In an otherwise healthy individual, anemia accompanied by an elevated protoporphyrin level is most commonly indicative of iron deficiency anemia.

Other laboratory tests used for the diagnosis of iron deficiency anemia include mean corpuscular volume (MCV), serum iron concentration and iron-binding capacity, and transferrin receptor concentration. A low MCV is most commonly associated with iron deficiency anemia or thalassemia trait; a high MCV but low hemoglobin is inconsistent with a diagnosis of iron deficiency and is more likely anemia caused by folate or vitamin B₁₂ deficiency.

The ratio of serum iron to iron-binding capacity (transferrin saturation) is decreased in individuals with iron deficiency. This measure is less frequently used than in the past because the samples used for measurements can be easily contaminated and its reproducibility is relatively poor.

Transferrin receptor concentration is a promising new indicator that should shortly become available for widespread use. The transferrin receptor concentration is elevated in individuals with iron deficiency anemia but not in those with inflammatory disease, a useful feature (Ferguson et al., 1992). For nutritional survey purposes, the combination of transferrin receptor, serum ferritin, and hemoglobin concentration determinations is likely to provide an excellent depiction of iron status (Cook et al., 1993).

Current information on the prevalence of iron deficiency anemia in the United States comes from data collected between 1976 and 1980 as part of NHANES II. In NHANES II, the prevalence of iron deficiency anemia (determined by MCV, transferrin saturation, and erythrocyte protoporphyrin) was about 9 percent (those below the 95 percent confidence interval; i.e., below the 2.5th percentile) in children 12 to 24 months of age (LSRO, 1984). For nonpregnant women of childbearing age, the prevalence of iron deficiency anemia found in NHANES II was 5 percent. Throughout the 1980s, the preva-

FRONT MATTER (R1-R12)

THE COMMITTEE (1-1)

MAJOR ISSUES (2-10)

RECOMMENDED GUIDELINES FOR PREVENTION, DETECTION, AND MANAGEMENT OF IRON DEFICIENCY ANEMIA (11-19)

RECOMMENDED GUIDELINES FOR PREVENTING AND TREATING IRON DEFICIENCY ANEMIA IN INFANTS AND CHILDREN (20-21)

RECOMMENDED GUIDELINES FOR PREVENTING AND TREATING IRON DEFICIENCY ANEMIA IN NONPREGNANT WOMEN OF CHILDBEARING AGE (22-23)

RECOMMENDED GUIDELINES FOR PREVENTING AND TREATING IRON DEFICIENCY ANEMIA IN PREGNANT WOMEN (24-25)

RECOMMENDATIONS FOR RESEARCH (26-31)

REFERENCES (32-36)

APPENDIXES (37-38)

A ACKNOWLEDGMENTS (39-40)

B IRON DEFICIENCY ANEMIA: A SYNTHESIS OF CURRENT SCIENTIFIC KNOWLEDGE AND U.S. RECOMMENDATIONS FOR PREVENTION AND TREATMENT (41-98)

C IRON-DEPENDENT PATHOLOGIES (99-112)

D DIETARY IRON: TRENDS IN THE IRON CONTENT OF FOODS, USE OF SUPPLEMENTAL IRON, AND THE FRAMEWORK FOR REGULATION OF IRON IN THE DIET (113-122)

E COMMITTEE AND STAFF BIOGRAPHIES (123-126)