Mean corpuscular

Other additional studies or pertinent information that lend support to this MRL An intermediate-duration gavage study in rats found decreased hematocrit and erythrocyte counts relative to before-treatment values (Galal et al. 1977), but this study had some limitations, including lack of a control group and disparities between text and tables. Another intermediate duration gavage study in male rats demonstrated dose-related significant decreases in mean corpuscular volume (Undeger et al. 2000). An effect on the erythrocyte is plausible because erythrocyte cholinesterase has a function in the control of erythrocyte permeability (Wills 1972). 

Evaluating the mean corpuscular volume (MCV) is the next step in an anemia work-up. It is classified as microcytic, normocytic, or macrocytic if the MCV is below, within, or above the normal range of 80 to 96 fIVcell, respectively. 

FIGURE 63-3. The anemia evaluation process. MCV, mean corpuscular volume Pb, lead TIBC, total iron binding capacity ACD, anemia of chronic disease. 

Closely monitor patients for efficacy and toxicity while they are receiving hydroxyurea. Monitor mean corpuscular volume (MCV) because it increases as the level of HbF increases. If the MCV does not increase with hydroxyurea use, the marrow may be unable to respond, the dose may not be adequate, or the patient may be noncompliant.27 HbF levels also can be monitored to assess response. Assess blood counts every 2 weeks during dose titration and then every 4 to 6 weeks once the dose is stabilized. Temporary discontinuation of therapy is warranted if the hemoglobin level is less than 5 g/dL (50 g/L or 3.1 mmol/L), the absolute neutrophil count is less than 2000/mm3 (2 x 109/L), platelets are less than 80,000/mm3 (80 x 109/L), or reticulocytes are less than 80,000/mm3 (80 x 109/L) if the hemoglobin is less than 9 g/dL (90 g/L or 5.6 mmol/L). Monitor for increases in serum creatinine and transaminases. Once the patient has recovered, hydroxyurea may be restarted with a dose that is 2.5 to 5 mg/kg less than the dose associated with the patient s toxicity. Doses then may be increased by 2.5 to 5 mg/kg daily after 12 weeks with no toxicity. 

MCH Mean corpuscular hemoglobin OCD Obsessive-compulsive disorder... 

MCHC Mean corpuscular hemoglobin concentration OD Right eye (oculus dexter)... 

MCV Mean corpuscular volume OGT Oral glucose tolerance test... 

Gd gestational day (Gl) = gastric intubation (GO) = gavage in oil Hemato - hematological incr. = increased IPTPP = isopropyl triphenyl phosphate LD = lethal dose, 50% kill LOAEL = lowest-observed-adverse-effect level M = male MCV = mean corpuscular volume MCHC = mean corpuscular hemoglobin concentration mo = month(s) Musc/skel = musculoskeletal NOAEL = no-observed-adverse-effect level NS = not specified NTE = neurotoxic esterase RBC red blood cell Resp = respiratory TBEP = tributoxyethyl phosphate TBP = tributyl phosphate TMP = trimethyl phosphate TNBP = tri-n-butyl phosphate TOP = trioctyl phosphate wk = week(s) x = times yr = year(s). 

F, female M, male MCH, mean corpuscular hemoglobin MCHC, mean corpuscular hemoglobin concentration MCV, mean corpuscular volume RBC, red blood cell RDW, red blood cell distribution TIBC, total iron-binding capacity. 

Macrocytic anemias are characterized by increased mean corpuscular volume (110 to 140 fL). One of the earliest and most specific indications of macrocytic anemia is hypersegmented polymorphonuclear leukocytes on the peripheral blood smear. Vitamin B12 and folate concentrations can be measured to differentiate between the two deficiency anemias. A vitamin B12 value of less than 150 pg/mL, together with appropriate peripheral smear and clinical symptoms, is diagnostic of vitamin B12-deficiency anemia. A decreased RBC folate concentration (less than 150 ng/mL) appears to be a better indicator of folate-deficiency anemia than a decreased serum folate concentration (less than 3 ng/mL). 

Calcium Mean corpuscular hemoglobin Occult blood... 

Mean corpuscular B-12 deficiency Reticulocytosis Iron deficiency... 

Again, the majority of these parameters are interrelated and highly dependent on the method used to determine them. Red blood cell count (RBC), platelet counts, and mean corpuscular volume (MCV) may be determined using a device such as a Coulter counter to take direct measurements, and the resulting data are usually stable for parametric methods. The hematocrit, however, may actually be a value calculated from the RBC and MCV values and, if so, is dependent on them. If the hematocrit is measured directly, instead of being calculated from the RBC and MCy it may be compared by parametric methods. 

In another 13-week study in Fischer 344 rats, male rats that received 1,4-dichlorobenzene at 300 mg/kg/day and above had decreased hematocrit levels, red blood cell counts, and hemoglobin concentrations (NTP 1987). None of these hematologic effects were consistently seen in female rats at the same dosage level however, a decrease in mean corpuscular volume was noted in females at doses of 600 mg/kg/day or more. In a parallel study in male and female B6C3Fj mice dosed with... 

Statistically significant decreases in hematocrit and increases in mean corpuscular hemoglobin concentration have been reported in men occupationally exposed to 0.46-0.75 ppm EGBE for 1-6 years." It was noted that changes were small, showed no relationship to exposure concentration, and were still within normal biological variability. 

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