laboratory evaluation of erythrocyte rbc haemoglobin packed cell volume mcv mch mchc rdw...

Laboratory evaluation of erythrocyte

RBCHaemoglobin

Packed cell volume

MCVMCH

MCHC

RDW

Reticulocyte

Blood film

Quantitative description of erythropoiesisAnaemia, polycythaemia

Qualitative description of erythropoiesisMicro-, normo-, nacrocytosis;Hypo-, normo-, hyperchromia

Reflects anisocytosis

Reflects bone marrow erythropoietic activityhypoproliferative, hyperproliferative

Final assessment of the disorderabnormal RBC (fragments)

MCV

• HCT/RBC• RBC 5.000.000/microliter• Hematocrit 50%• The volume of RBC in 1 microliter• 0,0000001 microliter• 0,0001 nanoliter• 0,1 picoliter• 100 femtoliter [fL]

MCV (Mean Corpuscular Volume)

• microcytic anemia

• normocytic anemia

• macrocytic anemia

MCHC

• hypochromia

• normochromia

• hyperchromia


RBCHaemoglobin

Packed cell volume

MCVMCH

MCHC

RDW

Reticulocyte

Blood film






RDWMCV: 86 flRDW: 10,5 % (Normal)

MCV: 86 flRDW: 19,0 % (Abnormal)

red cell populations with higher than normal RDW are termed heterogenousthose with normal RDW are homogeneousanisocytosis is a general term reflecting increased variation in the size of red blood cells. The MCV will be within normal limits, but RDW will be increased.


RBCHaemoglobin

Packed cell volume

MCVMCH

MCHC

RDW

Reticulocyte

Blood film






Reticulocyte

Variation usually affects a continuum of red cell sizes, but occasionally two distinct red cell populations can be observed– sideroblastic anemia– red cell transfusion

Reticulocyte count • the number of reticulocytes is reported as a percentage

of the total red cells – 0.5-2.5%• when the red cell count is low, the percentage of

reticulocytes is inaccurately high, suggesting that more reticulocytes are present than there are in reality.

For instance: – A normal person with an rbc count of 5,000,000 /microliter and an

absolute reticulocyte count of 50,000 /microliter would have a relative retic count of 1.0%.

– An anemic person with 2,000,000 rbc's/microliter and the same 50,000 retics/microliter would have an apparently "abnormal" relative retic count of 2.5 % and could be misdiagnosed

Reticulocyte index (RI)

• A value of 45 is usually used as a normal hematocrit.• Hematocrit (%)......Retic survival (days)/maturation correction

36-45 1.0 26-35 1.5

16-25 2.0 15 and below 2.5

• So in a person whose reticulocyte count is 5%, hemoglobin 7.5 g/dL, hematocrit 25%, the RI would be:

5 x (25/45) /2 = 1.4• RI 1.0 – 2.0 for a healthy individual. • RI < 2 with anemia indicates decreased production

of reticulocytes and RBC• RI > 2 with anemia indicates hemolysis

Hypoproliferative Anemia• Microcytic

– iron deficiency anemia

– thalassemia (decreased globin chain synthesis)

– sideroblastic anemia (decreased porphyrin synthesis)

– anemia of chronic disease

• Macrocytic

– megaloblastic anemia (B12, folate deficiency)

Hemolytic Anemia

Increased RBC turnover• RI• Serum unconjugated bilirubin

• Haptoglobin concentration• Serum LDH

Hemolysis• Hereditary disorders include erythrocyte membrane and enzymatic defects and

hemoglobin abnormalities. Some hereditary disorders include the following:– G-6-PD deficiency

– Hereditary spherocytosis

– Sickle cell anemia

• Acquired hemolytic conditions can be due to immune disorders, toxic chemicals and drugs, antiviral agents (eg, ribavirin), physical damage, and infections. They can include the following:

– autoimmune hemolytic anemia (AIHA)

– disseminated intravascular coagulation (DIC)

– hemolytic uremic syndrome (HUS)

– thrombotic thrombocytopenic purpura (TTP)

– defective prosthetic cardiac valves

• Autoimmune hemolytic anemia and hereditary spherocytosis are classified as examples of extravascular hemolysis because the RBCs are destroyed in the spleen and other reticuloendothelial organs (RES).

• Intravascular hemolysis occurs in hemolytic anemia due to prosthetic cardiac valves, G-6-PD deficiency, thrombotic thrombocytopenic purpura, disseminated intravascular coagulation

• Fragmented erythrocytes (schistocytes)


RBCHaemoglobin

Packed cell volume

MCVMCH

MCHC

RDW

Reticulocyte

Blood film






Variation in shape• poikilocytosis

– poikilocyte is pear-shaped and so also called a teardrop cell

• poikilocytosis can refer to an increase in abnormal red blood cells of any shape where they make up 10% or more of the total population.

Megaloblastic anemias• macrocytic anemia with thrombocytopenia and a decreased reticulocyte

count– MCV can range from 100-150 fL or greater

• hypersegmented neutrophils can be observed on the peripheral smear – Hypersegmented neutrophils contain 5 or more lobes, while normal

neutrophils contain 3-4 lobes

• macrocytes are oval and have been called macroovalocytes. – In persons with severe anemia, macrocytes with nuclear remnants and

erythrocytes with megaloblastic nuclei can be present in the peripheral blood

– Macrocytes can be found in the peripheral blood in patients with liver disease or hemolytic anemia and usually do not have oval features

• increased LDH and indirect bilirubin levels along with a decreased reticulocyte count suggest ineffective hemopoiesis in which intramedullary hemolysis is occurring.– LDH level is an excellent indication of response to or failure of therapy

laboratory evaluation of erythrocyte rbc haemoglobin packed cell volume mcv mch mchc rdw...

Documents

red cell count

rbc count

distinct red cell populations

continuum of red cell

normal rdw

normal person

volume of rbc

normal hematocrit