Mentzer index

The Mentzer index, described in 1973 by Mentzer,^[1] is said to be helpful in differentiating iron deficiency anemia from beta thalassemia.^[2] If a CBC indicates microcytic anemia, the Mentzer index is said to be a method of distinguishing between them. In practice, the Mentzer index is not a reliable indicator and should not, by itself, be used to differentiate. Indeed, the relevance of the index may be questioned, as the presence of iron deficiency is easily determined by measuring the serum ferritin level, which should be obtained routinely in all cases of microcytic anemia. In addition, it would be possible for a patient with a microcytic anemia to have both iron deficiency and thalassemia, in which case the index would only suggest iron deficiency. (RWP 8-15-13)

The index is calculated from the results of a complete blood count. If the quotient of the mean corpuscular volume (MCV, in fL) divided by the red blood cell count (RBC, in Millions per microLiter) is less than 13, thalassemia is said to be more likely. If the result is greater than 13, then iron-deficiency anemia is said to be more likely.^[3]

The principle involved is as follows: In iron deficiency, the marrow cannot produce as many RBCs and they are small (microcytic), so the RBC count and the MCV will both be low, and as a result, the index will be greater than 13. Conversely, in thalassemia, which is a disorder of globin synthesis, the number of RBC's produced is normal, but the cells are smaller and more fragile. Therefore, the RBC count is normal, but the MCV is low, so the index will be less than 13. (In practice, the MCV has to be extremely low and/or the RBC extremely high to produce an index of less than 13, something rarely encountered, further calling into question the usefulness of the index. - RWP 8-15-13)

References

↑ Mentzer WC (April 1973). "Differentiation of iron deficiency from thalassaemia trait". Lancet. 1 (7808): 882. doi:10.1016/S0140-6736(73)91446-3. PMID 4123424.
↑ Ntaios G, Chatzinikolaou A, Saouli Z, et al. (July 2007). "Discrimination indices as screening tests for beta-thalassemic trait". Ann. Hematol. 86 (7): 487–91. doi:10.1007/s00277-007-0302-x. PMID 17476506.
↑ Joseph Mazza (15 January 2002). Manual of clinical hematology. Lippincott Williams & Wilkins. pp. 152–. ISBN 978-0-7817-2980-2. Retrieved 4 June 2010.

Myeloid blood tests (CPT 85002–85999)

Clotting

CBC Platelet count Mean platelet volume vWF: Ristocetin-induced platelet aggregation

clotting factors:	Prothrombin time Partial thromboplastin time Thrombin time Activated clotting time

other/general:	coagulation Bleeding time animal enzyme Reptilase time Ecarin clotting time Dilute Russell's viper venom time Thromboelastography Thrombodynamics test

fibrinolysis:	Euglobulin lysis time D-dimer

Red blood cell indices

CBC	RBC count Hematocrit Hemoglobin

ratios:	Mean corpuscular hemoglobin Mean corpuscular hemoglobin concentration Mean corpuscular volume Red blood cell distribution width

Fetal hemoglobin:	Apt–Downey test Kleihauer–Betke test

Other	Reticulocyte index Haptoglobin Mentzer index

CFU-GM

Other

Eponymous medical signs for hematology

Inclusion bodies	Red blood cell Cabot rings Howell–Jolly body Pappenheimer bodies Heinz body Neutrophil Döhle bodies Plasma cell Russell bodies Myeloblast Auer rod Histiocyte Birbeck granules

Tests	Apt test Coombs test

Other	Arneth count Mentzer index Virchow's triad Anaemia Pagophagia

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