Letter to the Editor: MCHC in lntravascular Hemolysis
Anemias have been classified by the size and hemoglobin content or red cells. Of the red cell indices, the mean corpuscular volume (MCV) has proven to be the most useful in the classification of anemia. The mean corpuscular hemoglobin concentration (MCHC) generally parallels the MCV, being reduced in iron deficiency anemia and thalassemia, and is reported to be elevated only in spherocytic anemias and certain hemoglobinopathies . Elevations in the MCHC to greater than 50.0 g/dl were reported in two patients with acute intravascular hemolysis due to clostridial septicemia. This increase was likely spurious due to the presence of extracellular hemoglobin. Experimental data and other cases of hemolytic anemia support this hypothesis.
Case 1: A 72-year-old male was admitted with fever and abdominal pain. The hemoglobin (HGB) was 15.3 gidl, red blood cell count (RBC) 4.96 X 10l2/L, hematocrit (HCT) 46.1%, MCV 93 fl, mean corpuscular hemoglobin (MCH) 30.8 pg, MCHC 33.2 g/dl, white cell count (WBC) 6.1 X 109/L, and platelet count (Plt) 139 X 109/L. Over the next few hours he began to bleed around the intravenous catheters, and the urine became dark. Repeat HGB was 7.8 g/dl, RBC 1.95 x 10l2/L, HCT 14.0%, MCV 71 fl, MCH 39.9 pg, MCHC 56.1 g/dl, WBC 15.6 X 109/L, Plt 48 X 109/L, prothrombin time (PT) 30.2 sec, and partial thromboplastin time (PTT) 63 sec. Blood cultures grew Clostridium perfringens. He became hypotensive and died. At autopsy, an acute clostridial hepatic abscess was detected.
Case 2: A 76-year-old male was admitted with fever and abdominal pain. The HGB was 1 1.6 g/dl, RBC 2.9 X lO'*/L, HCT 23.0%, MCV 80 fl, MCH 40 pg, MCHC 50.1 g/dl, WBC 26.6 X 109/L, and Plt 37 x 109/L. He died with a cardiac arrest. At autopsy, acute cholecystitis and a clostridial hepatic abscess were identified. Blood cultures grew Clostridium perlfringens.