Der Anteil des Blutvolumens, der von roten Blutkörperchen eingenommen wird. Sinkt bei Anämie und Blutverlust, steigt bei Dehydration und Hypoxie.
Andere Namen:Hematocrit, packed cell volume (PCV)Abschnitt:Blutzellen
Aktualisiert: 29. August 2026·MedProtect Redaktionsteam Referenzinformationen — keine Diagnose oder Verschreibung
Kurz gesagtHematocrit is the percentage of blood made up of red cells. Typical adult values are 37–48% for men and 34–43% for women; newborns run higher at 45–61%. The percentage moves with both the red cell mass and the plasma volume, which is why dehydration raises it and pregnancy lowers it.
Referenzbereiche
Gruppe
Referenzbereich
Erwachsene Männer
37–48%
Erwachsene Frauen
34–43%
Neugeborene
45–61%
Säuglinge
32–42%
Common reference values from the MedlinePlus Medical Encyclopedia. Intervals vary between laboratories and with smoking and altitude — the range on the report applies.
Wert prüfen
Enter the number from your lab report — see how it compares with the typical range. Mind the units shown in the chosen row.
A rough comparison with a typical range, not a diagnosis. Reference ranges vary between laboratories — check the range on your own report and let a clinician interpret the result.
Was dieser Marker ist
If a tube of blood is spun down, the red cells pack at the bottom and the straw-colored plasma stays on top. Hematocrit is simply the height of the red layer as a percentage of the whole column — a result of 42% means 42% of the blood volume is red cells.
The measurement depends on both the number and the size of red cells, so it moves together with the RBC count and hemoglobin. The three lines are reported together in the CBC and are read as a set: anemia shows up in all of them, and their proportions hint at the cause.
Because hematocrit is a ratio, it is sensitive to plasma volume as much as to red cells. Dehydration concentrates the blood and raises the percentage; pregnancy and overhydration dilute it and lower the percentage without any change in the actual number of cells.
Providers order the test — almost always within a CBC — for fatigue, suspected bleeding, chronic kidney disease, before and after surgery, during pregnancy, and to monitor treatments that can suppress the bone marrow.
Wenn er erhöht ist
DehydrierungThe most common cause: with less plasma water the same red cells take up a larger share of the volume. Severe diarrhea is the textbook example.
Chronic low oxygenLung disease, congenital heart disease, and cor pulmonale drive red cell production up, and the percentage follows.
RauchenCarbon monoxide exposure reduces oxygen delivery and the body compensates with more red cells.
Polycythemia veraA marrow disorder that overproduces red cells; a persistently high hematocrit without another explanation leads here.
Kidney TumoreRenal cell carcinoma and some cysts secrete erythropoietin and push red cell production up.
AltitudeThe percentage climbs naturally over the first weeks at high altitude and drifts back after descent.
Wenn er erniedrigt ist
BlutungRecent injury or chronic hidden blood loss removes red cells faster than they are replaced.
Anemia of any causeToo few or too small red cells — iron, B12, folate, B6, or copper deficiency among the causes — lower the red cell share.
Bone marrow suppressionLeukemia, other cancers, medicine toxicity, radiation, and infection can all slow the marrow's output of new red cells.
Chronische NierenerkrankungLess erythropoietin means a weaker production signal and a gradually falling hematocrit.
SchwangerschaftPlasma volume expands faster than red cell mass, so the percentage dips — a normal physiological change that is still monitored.
OverhydrationExcess fluid dilutes the blood; the percentage falls while the actual cell count is unchanged.
Was das Ergebnis verfälschen kann
Diese Faktoren können den Wert ohne Krankheit verschieben — lohnt sich zu prüfen, bevor eine Wiederholung erfolgt:
Hydration on the test daySchwangerschaftRauchenAltitude of residenceRecent bleeding or transfusionMedicines affecting the marrow
Vorbereitung
No special preparation is needed for a hematocrit test. It is one line of the CBC; fasting requirements would come only from other tests in the same draw. Because hydration shifts the percentage, the circumstances of the day — a stomach bug, a long flight — are worth mentioning.
Wann eine Wiederholung sinnvoll ist
An off-range percentage is commonly rechecked after rehydration or recovery from the provoking event. In anemia treatment or polycythemia monitoring the test is repeated on the treating provider's schedule to track the trend.
Wer dieses Ergebnis üblicherweise überprüft
Ein Ergebnis außerhalb des Referenzbereichs wird üblicherweise überprüft von:your GP or primary care doctor; a hematologist if a blood disorder is suspected. Bringen Sie Ihren Laborbericht und alle früheren Ergebnisse zum Termin mit.
Namen auf Laborberichten
Ihr Bericht kann einen dieser Namen verwenden: HCTHctPacked cell volumePCV
Einheiten
Gemessen in:%
%=L/L
L/L = % × 0.01 (1% = 0.01 L/L)
Mehrere Marker in Ihrem Bericht?
See how MedProtect explains results in the app: the whole report, a check of the recognized values, and a clear breakdown.
Hemoglobin measures the oxygen-carrying protein concentration; hematocrit measures the volume share of red cells. As a rough rule the hematocrit percentage is about three times the hemoglobin number, and the two move together.
Why is my hematocrit high when I feel fine?
The commonest benign reason is dehydration on the day of the draw. Smoking and altitude do the same. A repeat test after normal drinking usually settles the question.
Does hematocrit change during pregnancy?
Yes — plasma volume grows faster than red cell mass, so the percentage drops. Prenatal CBCs track it to separate this normal dilution from true iron-deficiency anemia.
Wir verwenden Cookies und Yandex.Metrika für Besuchsstatistiken — ohne Werbe-Tracking und ohne Session-Aufzeichnung. Der Zähler wird erst nach Ihrer Zustimmung geladen. Datenschutzerklärung.