All articles starting with H

Hemodiafiltration

Hemodiafiltration is a kidney-failure blood-purification treatment combining the diffusive solute removal of hemodialysis with the convective removal of hemofiltration, clearing middle molecules and lowering mortality in randomized trials.

Hemodialysis

Hemodialysis filters wastes, extra salt, and water from blood through a dialyzer for kidney failure; in-center three times weekly or home schedules; access via AV fistula, graft, or catheter; invented by Willem Kolff in 1943.

Hemodilution

Hemodilution is the deliberate dilution of a patient's blood to reduce transfusions. In acute normovolemic hemodilution, blood is withdrawn after anesthesia and reinfused after surgery.

Hemodynamic assessment of pulmonary hypertension

Hemodynamic assessment of pulmonary hypertension is the measurement of pressures in the lungs' arteries, chiefly by right-heart catheterization, to diagnose pulmonary hypertension and classify it as pre- or post-capillary.

Hemodynamic monitoring

Hemodynamic monitoring is the measurement of circulatory variables, chiefly blood pressure and cardiac output, to guide treatment in critically ill patients, using tools from cuff pressure to invasive catheters.

Hemodynamics

Hemodynamics is the study of the physical principles governing blood flow and blood pressure in the cardiovascular system, relating the heart's driving pressure, vascular resistance, and flow.

Hemofiltration

Hemofiltration, also called CAVH or CVVH in continuous form, is a convective renal replacement technique removing water and middle molecules across a permeable membrane with replacement fluid; first performed by Peter Kramer in 1977 in Göttingen.

Hemoglobin

Hemoglobin (Hb, HbA) is the tetrameric heme protein in red blood cells carrying oxygen and CO2; key facts: cooperative binding, Bohr effect, HbF switch, sickle/thalassemia variants, HBOCs unapproved.

Hemoglobin Bart's fetalis syndrome

Hemoglobin Bart's fetalis syndrome, also called hemoglobin Bart's hydrops fetalis or alpha-thalassemia major, is the most severe form of alpha-thalassemia, caused by deletion of all four alpha globin genes and usually fatal without intrauterine transfusions.

Hemoglobin C

Hemoglobin C (HbC, HBB Glu6Lys) is a beta-globin variant causing red cell dehydration and crystals. HbAC trait is asymptomatic; HbCC causes mild anemia; HbSC is sickle cell disease with prominent retinopathy.

Hemoglobin C disease

Hemoglobin C disease (HbCC) is an autosomal recessive hemoglobinopathy from a beta-globin Glu6Lys mutation, causing mild hemolytic anemia, splenomegaly, and gallstones with normal life expectancy; distinct from HbC trait and HbSC disease.

Hemoglobin C-beta-thalassemia syndrome

Hemoglobin C-beta-thalassemia (HbC-BT, C-beta-thalassemia) is a compound heterozygous hemoglobinopathy combining HbC and a beta-thalassemia mutation, causing mild to moderate microcytic hemolytic anemia with splenomegaly, mainly in people of African descent.

Hemoglobin D disease

Hemoglobin D disease (Hb D-Punjab, Hb D-Los Angeles) is a beta-globin variant (β121 Glu→Gln, HBB c.364G>C) common in Punjab, India; benign alone, severe with Hb S.

Hemoglobin E

Hemoglobin E (HbE, Glu26Lys, HBB c.79G>A) is a common Asian beta-globin variant that is both a structural hemoglobin change and a mild beta-thalassemia mutation; HbE/β-thalassemia causes about half of severe beta thalassemia.

Hemoglobin E disease

Hemoglobin E disease (Hb EE), a benign hemoglobinopathy from a codon 26 beta-globin mutation common in Southeast Asia; trait is asymptomatic, but Hb E/beta-thalassemia causes about half of severe beta-thalassemia worldwide.

Hemoglobin E-beta-thalassemia syndrome

Hemoglobin E-beta-thalassemia (HbE-BT, E-beta-thalassemia) is an autosomal recessive beta-thalassemia of compound heterozygotes for HbE and beta-thalassemia, predominant in Southeast Asia, ranging from mild intermedia-like anemia to thalassemia major.

Hemoglobin electrophoresis

Hemoglobin electrophoresis is a blood test that separates and measures hemoglobin types (HbA, HbA2, HbF, HbS, HbC, HbE) by electric charge to diagnose sickle cell disease, thalassemia, and other hemoglobinopathies.

Hemoglobin H disease

Hemoglobin H disease (HbH disease, alpha-thalassemia intermedia): inherited anemia from inactivation of three of four alpha-globin genes; excess beta chains form unstable HbH tetramers; non-deletional forms are more severe.

Hemoglobin M disease

Hemoglobin M disease (M hemoglobinopathy; methemoglobinemia, beta type) is an autosomal dominant congenital methemoglobinemia from His-to-Tyr globin variants (Hb M-Boston, M-Iwate, M-Saskatoon, M-Milwaukee) causing benign lifelong cyanosis needing no treatment.

Hemoglobin variants

Hemoglobin variants, also called Hb variants, are abnormal forms of hemoglobin produced by globin gene mutations; more than 1000 are known, some causing erythrocytosis or cyanosis.

Hemoglobin, beta-type

Hemoglobin, beta-type (beta-globin, HBB gene, 11p15.4) is the beta chain of the α2β2 hemoglobin tetramer, one of the developmentally regulated beta-like globin genes; mutations cause sickle cell disease and beta-thalassemia.

Oct 20, 2026

Hemoglobinometry

Hemoglobinometry (haemoglobinometry): measurement of blood hemoglobin concentration to screen and diagnose anemia. Cyanmethemoglobin method and automated analyzers are reference standards; HemoCue dominates point-of-care field testing; WHO 2024 guidance favors venous blood.

Hemolymph

Hemolymph (haemolymph) is the blood-analogous circulatory fluid of mollusks, arthropods, and insects in open circulatory systems, combining blood and lymph roles, carrying hemocytes and often copper-based hemocyanin rather than red-cell hemoglobin.

Hemolysis

Hemolysis is premature red blood cell destruction with hemoglobin release, causing hemolytic anemia; covers intravascular vs extravascular mechanisms, lab markers (haptoglobin, LDH, DAT), hereditary and immune causes, complement inhibitors, and 2023 sickle cell gene therapies.

Hemolysis (microbiology)

Hemolysis in microbiology: bacterial lysis of red blood cells on blood agar, read as alpha (partial, green), beta (complete, clear), or gamma (none) patterns caused by hemolysins used to identify streptococci, staphylococci, and other pathogens.

Hemolysis assay

A hemolysis assay is a bench biology method that measures rupture of red blood cells by spectrophotometrically detecting the hemoglobin they release, reporting membrane damage as a hemolysis percentage.

Hemolytic anemia

Hemolytic anemia: premature red blood cell destruction (normal lifespan ~120 days) outpacing marrow production. Covers extravascular vs intravascular hemolysis, Coombs/DAT classification, warm/cold AIHA, G6PD deficiency, sickle cell, hereditary spherocytosis, and treatments including steroids, rituximab, eculizumab, and sutimlimab.

Hemolytic anemia due to glucophosphate isomerase deficiency

Hemolytic anemia due to glucophosphate isomerase deficiency, also known as GPI deficiency, is a rare inherited anemia beginning in infancy, caused by a faulty glycolytic enzyme.

Hemolytic anemia due to pyrimidine 5' nucleotidase deficiency

Hemolytic anemia due to pyrimidine 5' nucleotidase deficiency (P5N deficiency, UMPH1 deficiency, CNSHA8, OMIM 266120): rare autosomal recessive NT5C3A red cell enzymopathy with mild-moderate hemolytic anemia, basophilic stippling, and erythrocyte pyrimidine nucleotide accumulation; also mimicked by lead poisoning.