Complete blood count

The blood picture is in medicine a standardized compilation of important findings from a blood sample. It gives an overview of the cellular components contained in the blood. It includes data on both the quantity of cellular blood components as well as on the morphology of (outer shape).

A distinction is made between the small and large blood picture.

Blood count tests are generally carried out from EDTA blood.

  • 4.2.1 Disorders of erythrocytes
  • 4.2.2 Disorders of platelet


The cellular blood components are red blood cells ( erythrocytes), white blood cells ( leukocytes) and platelets ( platelet older name by shilling ). Normally, the human blood consists of about 43 to 50 % (men) and to 37 to 45 % ( women) in blood cells. The proportion of the cellular components of the total volume of the sample is called the hematocrit. After separation of cellular components (eg, by centrifugation) remaining liquid blood is the blood plasma, which contains electrolytes, coagulation factors and other plasma proteins. If you let blood sit for a while, then sets a clotting reaction, which clotting factors are activated and, together with the cellular components (in particular platelets ) a clot (thrombus ). The supernatant is composed of plasma without clotting factors and is then called blood serum.

" Small " blood count

The following information provides reference values ​​for adults. Reference values ​​for children, especially for infants, partly differ significantly from this.

" Large " blood count

The complete blood count includes in addition to the small blood picture, containing only the total white, the differential blood count. This is a detailed breakdown from which sub-groups, the leukocytes (white blood cells) are composed. This differential blood count may be, that is created automatically or manually microscopy. Microscopic counting of a blood smear or by automated counting machines the percentage of individual blood cell types are determined. Microscopic counting is complex and quantitatively less precise, but often the final qualitative evaluation is imperative. Thus, pathogenic cell lines such as atypical lymphocytes ( Virozyten ) are machine often not properly allocated and diagnostically relevant information will be lost. The shape of red blood cells (erythrocytes) is assessed with a blood smear.

Blood disorders

The wide variety of health conditions can lead to an eye-catching blood count.

Quantitative changes

Deviations of the Retikulozytenanzahl

Although the proportion of reticulocytes is not normally influenced in the routine, it is an important measure of the red blood cell formation in bone marrow. The measured value here can distinguish whether it is a revenue disorder in which the reticulocyte is increased, or an educational disorder in which the reticulocyte is normal or decreased, is.

Disorders of the erythrocyte

Appearance in the blood smear and its importance or occurrence:

  • Makrozyt: diameter > 10 microns, increased volume, but normal shape; in alcoholism
  • Megalozyt: enlarged, hyperchromic ( more colored ) oval erythrocyte; with vitamin B12 deficiency, folic acid deficiency, iron deficiency, thalassemia
  • Mikrozyt: diameter < 7 microns, degraded volume, but normal shape; in iron deficiency, Thalasämie
  • Poikilozyt: abnormally shaped erythrocytes ( coat -, club-, pear-shaped ); in severe anemia
  • Reticulocyte: erythrocyte young Coreless with reticular core residues; to 1.5% of normal, with increased red blood cell formation increases (eg, hemolysis)
  • Schistozyt (also Fragmentozyt ): torn erythrocyte; with HUS ( hemolytic- uremic syndrome, mechanical hemolysis ( eg artificial heart valve ) )
  • Sickle cell: erythrocyte short-lived (< ​​42 days), which takes under oxygen deprivation crescent shape; Sickle cell anemia
  • Sphärozyt: Ball cell; with ball -cell anemia
  • Target cell: erythrocyte with abnormal color distribution (hemoglobin in the center and a ring at the edge ); in thalassemia, hemolytic anemia, severe iron deficiency anemia
  • Anisocytosis: " no cell is equal to the other "; in all anemias
  • Anulozyt: ring-shaped erythrocytes with low hemoglobin content and the resulting pallor; in iron deficiency anemia
  • Basophilic stippling: distributed point-like basophilic substance ( dark Tüpflung ) in erythrocytes and increased erythropoiesis; for lead poisoning and thalassemia
  • Dakrozyt: tear drop shape; at osteomyelosclerosis
  • Elliptozyt: oval erythrocyte; with rare hereditary elliptocytosis
  • Heinz inclusion bodies: degenerate, intracellular hemoglobin, which is visible only after special staining; at toxic, hemolytic anemia, methemoglobinemia, G6P -DH deficiency
  • Howell - Jolly bodies: core residues in erythrocytes; after splenectomy.
  • Anemia (anemia ) - decrease in hemoglobin concentration in the blood caused by too little red blood cells and / or reduction in MCHC
  • Polycythemia (blood fullness) - too many red blood cells
  • Polycythemia vera ( over normal cell proliferation in the blood) - too many red blood cells

Disorders of leukocytes

  • Leukocytosis - too many leukocytes
  • Left shift - increased incidence of immature granulocytes
  • Right shift - increased incidence übersegmentierter (old ) granulocytes

Disorders of platelet

  • Thrombocytopenia or thrombocytopenia - too few platelets
  • Thrombocytosis - too many platelets

Qualitative changes

Disorders of the erythrocyte

  • Anisocytosis
  • Storage - abnormal storage, such as " rouleaux formation "
  • Microcytosis - too small erythrocytes
  • Macrocytosis - too large erythrocytes
  • Poikilocytosis
  • Polychromasia - dyeability pathologically changed or not mature erythrocytes with acidic and basic dyes (usual staining according to Pappenheim = May- Grünwald - Giemsa stain )
  • Thalassemia and other Erythorozyten the relevant genetic defects - Leads to deformed / smaller / larger Erythorozyten.
  • Cell inclusions - inclusions, such as Cabot rings or basophilic stippling

Disorders of platelet

  • Thrombanisozytose - different sized platelets ( = increased distribution width of the platelet volume )