Can moderate burr cells in a complete blood count (CBC) with differential be a lab error in an asymptomatic adult patient with no anemia, normal differential, and no significant past medical history?

Moderate Burr Cells in an Asymptomatic Patient: Lab Error vs. Clinical Significance

In an asymptomatic patient with no anemia, normal differential, and moderate burr cells on CBC, this finding warrants clinical correlation and repeat testing rather than dismissal as lab error, as burr cells can indicate serious underlying conditions even in the absence of overt hematologic abnormalities.

Clinical Significance of Burr Cells

Burr cells (echinocytes) are not benign findings and carry significant prognostic implications:

• Burr cells are independently associated with a 3-fold increase in 30-day mortality risk (27.3% mortality rate) in hospitalized patients, even when controlling for other clinical variables 1
• This mortality association persists across diverse clinical presentations and is most commonly found in patients with renal or liver failure 1
• Burr cells can indicate acquired membrane abnormalities related to metabolic derangements, even before other laboratory abnormalities become apparent 2

Why This Is Unlikely to Be Lab Error

Several factors argue against dismissing this as artifact:

• True echinocytes persist in fresh specimens and are reproducible on repeat testing, whereas artifact-related burr cells (crenation) typically occur with specimen aging or improper storage 3
• The finding is reported as "moderate" rather than rare, suggesting a consistent pattern rather than random artifact 3
• Laboratory professionals distinguish true burr cells from crenation artifact based on morphologic features and specimen quality during manual differential review 3

Recommended Diagnostic Approach

Immediate steps:

• Repeat CBC with manual differential on a fresh specimen to confirm the presence of burr cells and exclude pre-analytical artifact 3
• Obtain comprehensive metabolic panel including renal function (BUN, creatinine), liver function tests (AST, ALT, bilirubin, albumin), and electrolytes to screen for occult organ dysfunction 1
• Measure serum LDH and haptoglobin to evaluate for hemolysis, as burr cells can be associated with hemolytic processes even without overt anemia 2

Additional targeted testing based on initial results:

• If renal dysfunction is present: assess for uremia-related echinocytosis 1
• If liver dysfunction is present: evaluate for chronic liver disease and consider alcohol history, as alcohol can directly alter erythrocyte membrane lipid composition leading to burr cell formation and hemolysis 2
• Review medication list for drugs that can cause echinocytosis
• Consider lipid panel, as alterations in plasma lipids can affect red cell membrane composition 2

Critical Clinical Pitfalls

Do not assume normal hemoglobin excludes significant pathology:

• Burr cells may represent early manifestation of progressive disease before anemia develops 2, 1
• The absence of anemia does not negate the prognostic significance of burr cell morphology 1
• Transfused red cells can acquire the burr cell morphology in the patient's circulation, indicating an ongoing pathologic process affecting the plasma or metabolic environment 2

Common underlying conditions to exclude:

• Chronic kidney disease (even early stages) 1
• Chronic liver disease (including occult alcoholic liver disease) 2, 1
• Hemochromatosis (can present with burr cells and hemolysis) 2
• Metabolic derangements affecting membrane lipid composition 2

Follow-Up Strategy

• If repeat testing confirms burr cells and metabolic workup is normal: close clinical follow-up with repeat CBC in 1-3 months is warranted 4
• If any metabolic abnormalities are identified: address the underlying condition and monitor hematologic parameters 4
• Document the finding clearly for future reference, as burr cells may be an early marker of evolving disease 1