Hemoglobin - hematocrit - erythrocyte count - erythrocyte indices - reticulocyte count - red cell production index - Erythrocyte sedimentation rate
Hemoglobin:
Hemoglobin concentration is a more precise term than hemoglobin since the amount of hemoglobin per unit volume (L) is measured. The hemoglobin concentration can vary considerably depending on the patient's state of hydration. Hemoglobin is usually measured spectrophotometrically.
Normal range: Men - g/L, women - g/L.
Hematocrit:
Hematocrit corresponds to the percentage of the cells in the blood volume. This value is expressed as a fraction (liter/liter) or in percent. Hematocrit is measured by the direct reading of a blood-filled tube that has previously been centrifuged, or it is calculated from the hemoglobin by an electronic cell counting device.
Normal range: Men - L/L or - %, women - L/L or - %. The general standard value is 0.45 L/L or 45%.
Erythrocyte or red cell count:
The erythrocyte count deals with red cell concentration per liter. The measurement can be done microscopically with a counting chamber or by means of an automated cell counter. In both methods, the leukocytes are counted too. Therefore, if the leukocyte count exceeds 100 x 109/L a correction of the erythrocyte count is necessary.
Normal range: Men - x 1012/L, women - x 1012/L.
Erythrocyte indices:
Erythrocyte indices are derived from the values of hemoglobin (Hb), hematocrit (Hc) and the erythrocyte count (Ec). They reflect erythrocyte volume and hemoglobin concentration in the erythrocyte.
Erythrocyte indices allow anemias to be defined more precisely. Therefore, based on the MCV, anemias can be classified as microcytic (iron deficiency anemia, thalassemia), normocytic (anemia of chronic disorders, anemia of renal disease), and macrocytic (megaloblastic anemia). The MCH classifies hypochromic (iron deficiency anemia, thalassemia) and normochromic (anemia of chronic disorders, anemia of renal disease). Usually, although not always, the terms microcytic/hypochromic, normocytic/normochromic and macrocytic/hyperchromic are paired.
Reticulocyte count
Since reticulocytes are not recognized by Wright staining, they must be made visible by the so-called supravital staining (staining of a non-fixed film). In this staining, the reticulocytes' net-like precipitates are recognizable. The reticulocytes are counted by microscopy in relation to the erythrocytes. The normal value is 0.5 to 2% of the erythrocytes. This value corresponds to the observation that the reticulocytes need around 1-2 days (approximately one hundredth of the erythrocytes' life span) to mature into erythrocytes. In absolute numbers, the normal range is - x 109/L.
Red cell production index
The younger the reticulocytes are when they are released from the bone marrow, the longer the maturation time and the longer the period of time in which they can be detected in the peripheral blood. Since this leads to falsely high values, it is recommended that a correction be done if polychromasia is present which indicates increased erythropoiesis.
Erythrocyte sedimentation rate
The sedimentation rate does not actually belong to the parameters of the red blood picture. However, since results of the sedimentation rate depend on different alterations of the erythrocytes, it will be discussed here. In cases of anemias and macrocytsis it is increased, while in cases of polycythemia, microcytosis and acanthocythosis is is diminished. An elevated fibrinogen (inflammation, infections, neoplasias) also leads to an increase of the erythrocyte sedimentation rate.
The erythrocyte sedimentation rate is an inexpensive test that can be performed quickly. Primarily, it is a non-specific indicator of chronic inflammatory disorders and can indicate the extent of the disorder. Since it increases with a 24-hour delay, a C-reactive protein assay is preferred in many places in acute inflammatory disorders. For diagnosis and follow-up of polymyalgia rheumatica and temporary arthritis, it is vitally important. In oncology, it is considered to be an important indicator of a relapse of Hodgkin disease. An elevated sedimentation rate due to paraproteins is seen in multiple myeloma. A sedimentation rate over 100 mm/h is almost always seen with a fatal underlying disease.
Normal range: Men - mm/1h, women - mm/1h.
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