|
|||||||||
|
|
|
|
|
|
|
|
|
|
|
BRIEF REPORT
From the Research and Pathology Services, Department of
Veterans Affairs, Memphis, TN; the Department of Pathology, University
of Tennessee, Memphis; and the Department of Pathology and Immunology,
Washington University, St Louis, MO.
Determination of the reticulocyte hemoglobin content (CHr)
provides an early measure of functional iron deficiency because reticulocytes are the earliest erythrocytes released into blood and
circulate for only 1 to 2 days. The CHr in 78 patients undergoing bone
marrow examination was measured to assess its clinical utility for the
diagnosis of iron deficiency. Twenty-eight patients were iron
deficient, based on the lack of stainable iron in the aspirate. The
diagnostic power of CHr is limited in patients with high mean cellular
volume (MCV) or red cell disorders such as thalassemia. However, when
patients with MCV more than 100 fL are excluded, receiver operator
curve analysis of CHr, ferritin, transferrin saturation, and MCV
demonstrates that CHr has the highest overall sensitivity and
specificity of these peripheral blood tests for predicting the absence
of bone marrow iron stores.
(Blood. 2002;99:1489-1491) Accurate, early diagnosis of iron deficiency
is essential because it may be the presenting sign of a
gastrointestinal malignancy.1 Numerous peripheral blood
tests are performed to diagnose iron deficiency, including ferritin,
transferrin saturation, serum iron, and mean cellular volume (MCV).
Serum ferritin of 12 µg/L or less is the most specific indicator of
iron deficiency.2 However, because it is an acute-phase
reactant, ferritin may be normal or increased in iron-deficient
patients with other medical problems. Because reticulocytes are the
earliest erythrocytes released into blood and circulate for only 1 to 2 days, the reticulocyte hemoglobin content (CHr) provides a measure of
iron available to red cells recently produced by the bone marrow. CHr
has been shown to be an early indicator of iron-restricted
erythropoiesis in patients receiving erythropoietin
therapy3-7 and is a strong predictor of iron deficiency in
children.8 However, a study evaluating the ability of CHr
to predict bone marrow iron stores has not been performed.
Subjects
Analytical methods
The average CHr in samples from 34 medical students was
30.8 ± 0.90 pg with a range of 28.8 to 32.9 pg. No significant
difference between male and female values was present. To determine its
efficacy in predicting bone marrow iron stores, CHr was measured in 78 patients undergoing bone marrow biopsy. Reasons for biopsy included anemia work-up (34%), benign hematologic disorders such as
thrombocytopenia or monoclonal gammopathy (22%), hematologic
malignancy (19%), lymphoma or multiple myeloma (19%), and other
malignancies (6%). As determined by the absence of stainable iron in
the bone marrow aspirate, 28 (36%) of the 78 patients were classified
as iron deficient. The average CHr in the iron-deficient patients was 28.3 ± 5.2 pg with a range of 21.0 to 38.6 pg, whereas in
iron-replete patients the average CHr was 30.2 ± 3.4 pg with a range
of 22.8 to 43.7 pg. Of the 28 iron-deficient patients, 17 had a CHr of 28.0 pg or less, giving an overall sensitivity for the assay of 60.7%
in this patient population (Table 1).
Because the CHr is the product of the cellular volume and cellular
hemoglobin concentration, patients with combined iron deficiency and
megaloblastic anemia may have a falsely elevated CHr because of the
high MCV associated with megaloblastosis. The MCV among iron-deficient
patients ranged from 61.9 to 120.9 fL, and 7 patients, all with CHr
less than 28 pg, had an MCV less than 81 fL. Of the iron-deficient
patients with CHr more than 28.0 pg, 5 had MCV of 100 fL or more. One
patient had a CHr of 30.5 pg, and the other 4 patients had CHr values between 36 and 38 pg. An iron-replete patient who developed
pancytopenia and megaloblastic anemia (MCV, 105 fL) secondary to
vitamin B12 deficiency had a CHr of 43.7 pg, 5 pg more than
any other patient in this study, further emphasizing the effects of
megaloblastic changes on CHr. When patients with MCV of 100 fL or more
(5 iron deficient and 5 iron replete) are excluded from analysis, the average CHr is 26.7 ± 3.9 pg in iron-deficient patients and
29.6 ± 2.6 pg in iron-replete patients, and the sensitivity for the assay increases to 73.9%. Of the 6 remaining iron-deficient patients with CHr more than 28.0 pg, 3 had been clinically diagnosed with iron deficiency and were receiving oral iron therapy. The CHr is
an early indicator of response to iron therapy, increasing within 2 to
4 days of the initiation of intravenous iron therapy.12 Thus, in patients receiving iron, the CHr may normalize before bone
marrow iron stores return, resulting in false-negative test values. The
3 other patients with chronic lymphocytic leukemia, B-cell lymphoma and
diabetes, arthritis and anemia, respectively, had no obvious reason for
normal CHr values. Of the iron-replete patients, 38 of 50 had CHr more
than 28.0 pg/cell, giving an overall specificity of 76.0% for the
assay (Table 1). Among the 12 patients with CHr of 28.0 pg or less, 2 had thalassemia, which is a recognized cause of low CHr,10
2 had a clinical diagnosis of iron deficiency, and 3 had hematologic
malignancy. The remaining 5 patients had various diseases such as
diabetes or arthritis and were examined for anemia evaluation.
The ability of CHr to predict bone marrow iron stores was compared with
that of ferritin, percentage of transferrin saturation, and MCV by
receiver operator curve (ROC) analysis (Figure
1). When patients with MCV 100 fL or more
are excluded from analysis, the area under the ROC curve is greater for
CHr than for the other 3 tests, indicating that it has the best overall
sensitivity and specificity for iron deficiency in the population of
patients tested.13,14 The optimal cutoff values for the
different assays were determined by ROC analysis and are presented
along with sensitivity, specificity, and positive and negative
predictive values in Table 1.
The clinical utility of CHr for the diagnosis of the anemia of chronic disease has not been carefully studied. The soluble transferrin receptor is another peripheral blood test that appears to predict iron deficiency more accurately than traditionally used tests15-17 and is particularly useful in differentiating iron deficiency anemia from the anemia of chronic disease.18-20 Both CHr and soluble transferrin receptor can be affected by other erythrocyte disorders that produce false-positive or false-negative test results for iron deficiency. Therefore, the correct diagnosis of iron deficiency requires that these tests are interpreted in the context of the patient's overall erythrocyte physiology, including knowledge of recent transfusions, iron therapy, vitamin B12 or folate deficiency, and the results of hemoglobin electrophoresis.
We thank the medical technologists in the Memphis VA Hospital Clinical Laboratories for assistance in obtaining the bone marrow aspirates and performance of the peripheral blood tests.
Submitted April 6, 2001; accepted October 10, 2001.
Supported by the Office of Research and Development, Department of Veterans Affairs.
The publication costs of this article were defrayed in part by page charge payment. Therefore, and solely to indicate this fact, this article is hereby marked "advertisement" in accordance with 18 U.S.C. section 1734.
Reprints: Alan Mast, Research Service-151, VA Hospital, 1030 Jefferson Ave, Memphis, TN 38104; e-mail: alan.mast3{at}med.va.gov.
1.
Rockey CD, Cello JP.
Evaluation of the gastrointestinal tract in patients with iron-deficiency anemia.
N Engl J Med.
1993;329:1691-1695 2. Ali MAM, Luxton AW, Walker WHC. Serum ferritin concentration and bone marrow iron studies: a prospective study. Can Med Assoc J. 1978;118:945-946[Medline] [Order article via Infotrieve]. 3. Brugnara C, Colella GM, Cremins J, et al. Effects of subcutaneous recombinant human erythropoietin in normal subjects: development of decreased reticulocyte hemoglobin content and iron-deficient erythropoiesis. J Lab Clin Med. 1994;123:660-667[Medline] [Order article via Infotrieve]. 4. Fishbane S, Galgano C, Langley RC Jr, Canfield W, Maesaka JK. Reticulocyte hemoglobin content in the evaluation of iron status of hemodialysis patients. Kidney Int. 1997;52:217-222[Medline] [Order article via Infotrieve]. 5. Bhandari S, Norfolk D, Brownjohn A, Turney J. Evaluation of RBC ferritin and reticulocyte measurements in monitoring response to intravenous iron therapy. Am J Kidney Dis. 1997;30:814-821[Medline] [Order article via Infotrieve]. 6. Mittman N, Sreedhara R, Mushnick R, et al. Reticulocyte hemoglobin content predicts functional iron deficiency in hemodialysis patients receiving rHuEPO. Am J Kidney Dis. 1997;30:912-922[Medline] [Order article via Infotrieve]. 7. Schaeffer RM, Schaeffer L. Hypochromic red blood cells and reticulocytes. Kidney Int. 1999;55:S44-S48[CrossRef].
8.
Brugnanra C, Zurakowski D, DiCanzio J, Boyd T, Platt O.
Reticulocyte hemoglobin content to diagnose iron deficiency in children.
JAMA.
1999;281:2225-2230
9.
Mohandas N, Kim YR, Tycko DH, Orlik J, Wyatt J, Groner W.
Accurate and independent measurement of volume and hemoglobin concentration of individual red cells by laser light scatter.
Blood.
1986;68:506-513
10.
D'Onofrio G, Chirillo R, Zini G, Caenaro G, Tommasi M, Micciulli G.
Simultaneous measurement of reticulocyte and red blood cell indices in healthy subjects and patients with microcytic and macrocytic anemia.
Blood.
1995;85:818-823 11. Cohen J. A coefficient of agreement for nominal scales. Educ Psychol Meas. 1960;20:37-46[CrossRef].
12.
Brugnara C, Laufer MR, Friedman AJ, Bridges K, Platt O.
Reticulocyte hemoglobin content (CHr): early indicator of iron deficiency and response to therapy [letter].
Blood.
1994;83:3100-3101
13.
Hanley JA, McNeil BJ.
The meaning and use of the area under a receiver operating characteristic (ROC) curve.
Radiology.
1982;143:29-36
14.
Hanley JA, McNeil BJ.
A method of comparing the areas under receiver operating characteristic curves derived from the same cases.
Radiology.
1983;148:839-843
15.
Kohgo Y, Niitsu Y, Kondo H, et al.
Serum transferrin receptor as a new index of erythropoiesis.
Blood.
1987;70:1955-1958
16.
Hueber HA, Beguin Y, Pootrakul P, Einspahr D, Finch CA.
Intact transferrin receptors in human plasma and their relation to erythropoiesis.
Blood.
1990;75:102-107
17.
Skikne BS, Flowers CH, Cook JD.
Serum transferrin receptor: a quantitative measure of tissue iron deficiency.
Blood.
1990;75:1870-1876 18. Ferguson BJ, Skikne BS, Simpson KM, Baynes RD, Cook JD. Serum transferrin receptor distinguishes the anemia of chronic disease from iron deficiency anemia. J Lab Clin Med. 1992;19:385-390.
19.
Pettersson T, Kivivuori SM, Siimes MA.
Is serum transferrin receptor useful for detecting iron-deficiency in anaemic patients with chronic inflammatory disease?
Br J Rheumatol.
1994;33:740-744
20.
Mast AE, Blinder MA, Gronowski AM, Chumley C, Scott MG.
Clinical utility of the soluble transferrin receptor and comparison with serum ferritin in several populations.
Clin Chem.
1998;44:45-51
© 2002 by The American Society of Hematology.
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 |
|
 |
|
  C. Ullrich, A. Wu, C. Armsby, S. Rieber, S. Wingerter, C. Brugnara, D. Shapiro, and H. Bernstein Screening Healthy Infants for Iron Deficiency Using Reticulocyte Hemoglobin Content JAMA, August 24, 2005; 294(8): 924 - 930. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. C. White Anemia Is a Poor Predictor of Iron Deficiency Among Toddlers in the United States: For Heme the Bell Tolls Pediatrics, February 1, 2005; 115(2): 315 - 320. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. Beutler, A. V. Hoffbrand, and J. D. Cook Iron Deficiency and Overload Hematology, January 1, 2003; 2003(1): 40 - 61. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 I. A. Cavill Iron status indicators: hello new, goodbye old? Blood, January 1, 2003; 101(1): 372 - 372. [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 |
 |
 |
|||||||
 |
 |
 |
 |
 |
 |
 |
 |
||
| Copyright © 2002 by American Society of Hematology Online ISSN: 1528-0020 | |||||||||
Top
Abstract
Introduction
, CHr; 
,
MCV; 
, transferrin saturation; O, Ferritin) for the detection of
absent bone marrow iron stores.
(A) All patients. (B) Patients with MCV more than 100 are excluded from
analysis. Diagnostic cutoff concentrations spanned the full range of
sensitivity and specificity for all analytes. Areas under the curves
(± 95% confidence interval) are presented in Table