Iatrogenic anemia, also known as nosocomial anemia or hospital-acquired anemia, is a condition in which a person develops

anemia Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, th ...

due to medical interventions, most frequently repeated

blood draw In medicine, venipuncture or venepuncture is the process of obtaining intravenous access for the purpose of venous blood sampling (also called ''phlebotomy'') or intravenous therapy. In healthcare, this procedure is performed by medical labo ...

s. Other factors that contribute to iatrogenic anemia include bleeding from medical procedures and dilution of the blood by

intravenous fluids Intravenous therapy (abbreviated as IV therapy) is a medical technique that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutrie ...

. People may receive

blood transfusions Blood transfusion is the process of transferring blood products into a person's circulation intravenously. Transfusions are used for various medical conditions to replace lost components of the blood. Early transfusions used whole blood, but mod ...

to treat iatrogenic anemia, which carries risks for complications like

transfusion reaction Blood transfusion is the process of transferring blood products into a person's Circulatory system, circulation intravenously. Transfusions are used for various medical conditions to replace lost components of the blood. Early transfusions used w ...

s and circulatory overload.

Incidence and cause

A 2013 study of over 400,000 people admitted to US hospitals found that 74% developed anemia at some point during their hospital stay. Iatrogenic anemia is of particular concern in

intensive care medicine Intensive care medicine, also called critical care medicine, is a medical specialty that deals with seriously or critically ill patients who have, are at risk of, or are recovering from conditions that may be life-threatening. It includes pro ...

, because people who are critically ill require frequent blood tests and have a higher risk of developing anemia due to lower

hemoglobin Hemoglobin (haemoglobin BrE) (from the Greek word αἷμα, ''haîma'' 'blood' + Latin ''globus'' 'ball, sphere' + ''-in'') (), abbreviated Hb or Hgb, is the iron-containing oxygen-transport metalloprotein present in red blood cells (erythrocyte ...

levels and impaired production of red blood cells (

erythropoesis Erythropoiesis (from Greek 'erythro' meaning "red" and 'poiesis' "to make") is the process which produces red blood cells (erythrocytes), which is the development from erythropoietic stem cell to mature red blood cell. It is stimulated by decrea ...

) at baseline. The average

intensive care unit 220px, Intensive care unit An intensive care unit (ICU), also known as an intensive therapy unit or intensive treatment unit (ITU) or critical care unit (CCU), is a special department of a hospital or health care facility that provides intensiv ...

(ICU) patient loses up to 660 mL of blood per week to laboratory testing. For each day in the ICU, it is estimated that a person's hemoglobin level falls by 5 g/L (0.5 g/dL), 80% of which is due to phlebotomy. On the second day of admission to the ICU, more than 70% of adults exhibit anemia, over half of whom will go on to require a

blood transfusion Blood transfusion is the process of transferring blood products into a person's circulation intravenously. Transfusions are used for various medical conditions to replace lost components of the blood. Early transfusions used whole blood, but mo ...

. In the

neonatal intensive care unit A neonatal intensive care unit (NICU), also known as an intensive care nursery (ICN), is an intensive care unit (ICU) specializing in the care of ill or premature newborn infants. Neonatal refers to the first 28 days of life. Neonatal care, as kn ...

(NICU), the issue is exacerbated by the patients' low body weight: it is estimated that during their first six weeks of life, infants in NICUs may lose 15−30% of their blood volume to blood draws. Premature babies often suffer from anemia of prematurity, which is caused by low production of

erythropoietin Erythropoietin (; EPO), also known as erythropoetin, haematopoietin, or haemopoietin, is a glycoprotein cytokine secreted mainly by the kidneys in response to cellular hypoxia; it stimulates red blood cell production (erythropoiesis) in the bo ...

(a hormone that stimulates red blood cell production) and the short lifespan of neonates' red blood cells, and is worsened by blood loss through phlebotomy. People who are receiving dialysis lose blood not only through sampling for laboratory tests, but from the dialysis process itself and from bleeding caused by accessing veins to attach the dialysis equipment. This iatrogenic anemia often occurs alongside the anemia caused by

kidney disease Kidney disease, or renal disease, technically referred to as nephropathy, is damage to or disease of a kidney. Nephritis is an inflammatory kidney disease and has several types according to the location of the inflammation. Inflammation can ...

. Another factor that contributes to anemia in hospitalized people is the use of

intravenous fluid Intravenous therapy (abbreviated as IV therapy) is a medical technique that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutrie ...

s. Infusion with large volumes of intravenous fluids dilutes the blood, causing a decreased hemoglobin and hematocrit level. This is not a true anemia, as no red blood cells are lost and the body eventually compensates for the effects of the infusion. However, the decreased hemoglobin and hematocrit may lead to unnecessary transfusion. Blood loss through surgery and through medical procedures such as central line placement also play a role, as does the use of certain drugs which can suppress the

bone marrow Bone marrow is a semi-solid tissue found within the spongy (also known as cancellous) portions of bones. In birds and mammals, bone marrow is the primary site of new blood cell production (or haematopoiesis). It is composed of hematopoietic ce ...

's ability to produce red blood cells.

Complications

People who develop iatrogenic anemia spend a longer amount of time in the hospital and have an increased risk of mortality. They are also more likely to receive

s, which carries risks for various conditions, including

transfusion reactions Blood transfusion is the process of transferring blood products into a person's circulation intravenously. Transfusions are used for various medical conditions to replace lost components of the blood. Early transfusions used whole blood, but mod ...

lung injury The lungs are the primary organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either side of t ...

, circulatory overload and

alloimmunization Alloimmunity (sometimes called isoimmunity) is an immune response to nonself antigens from members of the same species, which are called alloantigens or isoantigens. Two major types of alloantigens are blood group antigens and histocompatibility ...

. After the initial development of anemia, further testing may be ordered to monitor and investigate the condition, which worsens the anemia and the attendant risks for complications.

Prevention

The volume of blood needed for most laboratory tests is lower than the amount that is commonly drawn; a 2008 study found that only 9% of the blood in standard sized blood tubes was used for testing. Using smaller tubes for blood tests can decrease the risk of anemia, but it may increase the risk of laboratory errors.

Point-of-care testing Point-of-care testing (POCT or bedside testing) is defined as medical diagnostic testing at or near the point of care—that is, at the time and place of patient care. This contrasts with the historical pattern in which testing was wholly or most ...

, meaning testing performed at a patient's bedside rather than in a

medical laboratory A medical laboratory or clinical laboratory is a laboratory where tests are conducted out on clinical specimens to obtain information about the health of a patient to aid in diagnosis, treatment, and prevention of disease. Clinical Medical labor ...

, typically uses much smaller blood volumes than conventional testing; however, as of 2019, there is insufficient evidence regarding the effects of point-of-care testing on iatrogenic anemia. The use of closed blood sampling devices, which return excess blood from blood draws or line flushes to the person's circulation, can decrease the amount of blood loss in hospitalized patients. Strategies to decrease the amount of blood tests ordered, such as clinician education and

auditing An audit is an "independent examination of financial information of any entity, whether profit oriented or not, irrespective of its size or legal form when such an examination is conducted with a view to express an opinion thereon.” Auditing ...

, or restricting test orders through the

electronic health record An electronic health record (EHR) is the systematized collection of patient and population electronically stored health information in a digital format. These records can be shared across different health care settings. Records are shared throu ...

, have also been investigated.

References

{{Medical harm Anemias Hematopathology Transfusion medicine Medical error