Anemia Screening

Excerpt

Anemia is a common finding in both inpatient and outpatient settings, defined as a decrease in circulating red blood cells (RBCs) or hemoglobin. This condition is often inadequately evaluated or managed. While frequently listed as a standalone diagnosis, anemia is actually a clinical sign that indicates an underlying condition, requiring further investigation to determine its cause. Anemia leads to reduced tissue oxygenation and can worsen the progression of many coexisting diseases. Despite this condition's vast impact on health, inconsistencies remain in both its formal definition and the protocols for screening.

Symptoms of anemia vary widely and may include fatigue, weakness, lightheadedness, headache, pallor or jaundice, tachycardia, palpitations, chest pain, shortness of breath, cold extremities, and claudication. The prevalence and severity of these signs and symptoms differ among individuals.

Anemia causes a reduction in the relative number of circulating RBCs or hemoglobin, leading to a corresponding decrease in oxygen delivery to tissues. However, the hemoglobin concentration that defines anemia varies based on sex, ethnicity, and age. Additionally, no consensus has been established regarding which patient populations warrant routine anemia screening. Furthermore, the threshold for initiating treatment and the treatment goals differ depending on medical specialty and underlying conditions.

In 2010, the World Health Organization (WHO) set diagnostic criteria for anemia, defining it as hemoglobin levels below 12 g/dL in premenopausal women and below 13 g/dL in both postmenopausal women and men of all ages. The journal Blood challenged these standards, citing limited WHO data and proposing new anemia thresholds based on race, gender, and age. According to these proposed standards, anemia should be defined as hemoglobin levels below 13.7 g/dL for White men aged 20 to 60 and below 13.2 g/dL for White men older than 60. White women of all ages were considered anemic at hemoglobin levels under 12.2 g/dL.

Although the journal acknowledged significant differences in hemoglobin levels among Black men and women, it did not establish diagnostic thresholds for these populations. Most current literature continues to use WHO standards for consistency.

Disagreement also exists among the U.S. Preventive Services Task Force (USPSTF), various medical academic institutions, and actual clinical practice regarding anemia screening guidelines. For example, the USPSTF evaluated anemia screening in asymptomatic children aged 6 to 24 months and concluded that evidence was insufficient to determine the benefits versus harms of screening in this population. In contrast, the American Academy of Family Physicians (AAFP) recommended universal anemia screening at 12 months of age, including hemoglobin measurement and an assessment of risk factors for iron deficiency and iron deficiency anemia (IDA).

A similar lack of consensus applies to screening in pregnant women. The USPSTF stated, "The evidence of the effect of routine screening for IDA in asymptomatic pregnant women on maternal health and birth outcomes is insufficient... and the balance of benefits and harms cannot be determined." The AAFP agreed with this position. However, the American College of Obstetricians and Gynecologists, in Practice Bulletin No. 95, advised, "All pregnant women should be screened for anemia and treated if necessary." At present, no guidelines recommend routine anemia screening for nongravid, otherwise healthy adults.