Mean corpuscular volume - wikipedia Mean corpuscular volume The mean corpuscular volume, or mean cell volume ( MCV ), is a measure of the average volume of a red blood corpuscle ( or red blood cell ). The measure is attained by multiplying a volume of blood by the proportion of blood that is cellular ( the hematocrit ), and dividing that product by the number of erythrocytes ( red blood cells ) in that volume. The mean corpuscular volume is a part of a standard complete blood count. In a laboratory test that computes MCV, erythrocytes are compacted during centrifugation. In patients with anemia, it is the MCV measurement that allows classification as either a microcytic anemia ( MCV below normal range ), normocytic anemia ( MCV within normal range ) or macrocytic anemia ( MCV above normal range ). Normocytic anemia is usually deemed so because the bone marrow has not yet responded with a change in cell volume. It occurs occasionally in acute conditions, namely blood loss and hemolysis. If the MCV was determined by automated equipment, the result can be compared to RBC morphology on a peripheral blood smear. Any deviation would usually be indicative of either faulty equipment or technician error, although there are some conditions that present with high MCV without megaloblastic cells. For further specification, it can be used to calculate red blood cell distribution width. Contents 1 Calculation 2 Interpretation 2.1 High 2.2 Low 3 Worked example 4 Derivation 5 References 6 See also Calculation To calculate MCV, the hematocrit ( Hct ) is divided by the concentration of RBCs ( ( RBC ) ) MCV = Hct ( RBC ) ( displaystyle ( \textit ( MCV ) ) = ( \frac ( \textit ( Hct ) ) ( ( ( \textit ( RBC ) ) ) ) ) ) Normally, MCV is expressed in femtoliters ( fL, or 10 L ), and ( RBC ) is the quantity expressed in millions per microliter ( 10 / μL ). The normal range for MCV is 80 -- 100 fL. For example, if the Hct = 42.5 % and ( RBC ) = 4.58 million per microliter ( 4,580,000 / μL ), then MCV = 0.425 4.58 ⋅ 10 6 / 10 − 6 L = 92.8 ⋅ 10 − 15 L = 92.8 fL ( displaystyle ( \textit ( MCV ) ) = ( \frac ( 0.425 ) ( 4.58 cdot 10 ^ ( 6 ) / 10 ^ ( - 6 ) , L ) ) = 92.8 cdot 10 ^ ( - 15 ) , L = 92.8 , ( \textit ( fL ) ) ) Use of volume - sensitive automated blood cell counters, such as the Coulter counter. In this type of apparatus, the red cells pass one - by - one through a small aperture and generate a signal directly proportional to their volume. Other automated counters measure red blood cell volume by means of techniques that measure refracted, diffracted, or scattered light. Interpretation The normal reference range is typically 80 - 100 fL. High In pernicious anemia ( macrocytic ), MCV can range up to 150 femtolitres. An elevated MCV is also associated with alcoholism ( as are an elevated GGT and a ratio of AST : ALT of 2 : 1 ). Vitamin B12 and / or folic acid deficiency has also been associated with macrocytic anemia ( high MCV numbers ). Low The most common causes of microcytic anemia are iron deficiency ( due to inadequate dietary intake, gastrointestinal blood loss, or menstrual blood loss ), thalassemia, sideroblastic anemia or chronic disease. In iron deficiency anemia ( microcytic anemia ), it can be as low as 60 to 70 femtolitres. In some cases of thalassemia, the MCV may be low even though the patient is not iron deficient. Worked example Measure Units Conventional units Conversion Hct 40 % Hb 100 grams / liter 10 grams / deciliter ( deci - is 10 ) RBC 5E + 12 cells / liter 5E + 6 cells / μL ( micro is 10 ) MCV = Hct / RBC 8E - 14 liters / cell 80 femtoliters / cell ( femto - is 10 ) MCH = Hb / RBC 2E - 11 grams / cell 20 picograms / cell ( pico - is 10 ) MCHC = Hb / ( Hct / 100 ) 250 grams / liter 25 grams / deciliter ( deci is 10 ) Derivation The MCV can be conceptualized as the total volume of a group of cells divided by the number of cells. For a real world sized example, imagine you had 10 small jellybeans with a combined volume of 10 μL. The mean volume of a jellybean in this group would be 10 μL / 10 jellybeans = 1 μL / jellybean. A similar calculation works for MCV. 1. Measure the RBC index in cells / μL. Take the reciprocal ( 1 / RBC index ) to convert it to μL / cell. 1 5 × 10 6 c e l l s / μ L = 2 × 10 − 7 μ L / c e l l ( displaystyle ( \frac ( 1 ) ( 5 \times 10 ^ ( 6 ) ) ) cells / mu L = 2 \times 10 ^ ( - 7 ) mu L / cell ) 2. The 1 μL is only made of a proportion of red cells ( e.g. 40 % ) with the rest of the volume composed of plasma. Multiply by the hematocrit ( a unitless quantity ) to take this into account. 2 × 10 − 7 μ L / c e l l × 0.4 = 8 × 10 − 8 μ L / c e l l ( displaystyle 2 \times 10 ^ ( - 7 ) mu L / cell \times 0.4 = 8 \times 10 ^ ( - 8 ) mu L / cell ) 3. Finally, convert the units of μL to fL by multiplying by 10 9 ( displaystyle 10 ^ ( 9 ) ). The result would look like this : 8 × 10 − 8 μ L / c e l l × 10 9 f L 1 μ L = 80 f L c e l l ( displaystyle 8 \times 10 ^ ( - 8 ) mu L / cell \times ( \frac ( 10 ^ ( 9 ) \fL ) ( 1 mu L ) ) = 80 ( \frac ( fL ) ( cell ) ) ) Note : the shortcut proposed above just makes the units work out : 10 × 40 ÷ 5 = 80 ( displaystyle 10 \times 40 div 5 = 80 ) References Jump up ^ Stanley L Schrier, MD ; Stephen A Landaw, MD ( 30 September 2011 ). `` Mean corpuscular volume ''. uptodate.com. Jump up ^ MedlinePlus Medical Encyclopedia : RBC indices Jump up ^ Tønnesen H, Hejberg L, Frobenius S, Andersen J ( 1986 ). `` Erythrocyte mean cell volume -- correlation to drinking pattern in heavy alcoholics ''. Acta Med Scand. 219 ( 5 ) : 515 -- 8. PMID 3739755. doi : 10.1111 / j. 0954 - 6820.1986. tb03348. x. See also Anemia : Differential Diagnosis Full blood count Mean corpuscular hemoglobin `` The template below ( Myeloid blood tests ) is being considered for merging. See templates for discussion to help reach a consensus. '' 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 Nitro blue tetrazolium chloride test Complete blood count Absolute neutrophil count Other Blood film Blood viscosity Erythrocyte sedimentation rate Retrieved from `` https://en.wikipedia.org/w/index.php?title=Mean_corpuscular_volume&oldid=787813435 '' Categories : Blood tests Talk Contents About Wikipedia Català Deutsch Español Français Hrvatski Italiano Nederlands 日本 語 Polski Português Slovenščina Srpskohrvatski / српскохрватски Svenska ไทย 中文 Edit links This page was last edited on 27 June 2017, at 18 : 14. 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Question: what does mcv stand for in blood test
Answer: mean corpuscular volume, or mean cell volume