Related Experiment Video
Updated: Apr 27, 2026

A Precision Medicine Tool for Measurement and Monitoring of Hemoglobin S in Sickle Cell Disease Patients Receiving Transfusion Therapy
Misleading hemoglobin A1c levels in a patient with paroxysmal nocturnal hemoglobinuria
Daniel Xia1, Randall McShine2, Anders H Berg3
1From the Department of Pathology, Beth Israel Deaconess Medical Center, Boston, MA, and.
Objectives:
We report a case of a patient with diabetes mellitus and unexpectedly low hemoglobin A1c results associated with paroxysmal nocturnal hemoglobinuria (PNH). We review the impact of shortened RBC half-life on the interpretation of hemoglobin A1c levels.
Methods:
Patient history and laboratory test results were obtained from electronic medical records and analyzed.
Results:
The patient's hemoglobin A1c declined in parallel to worsening anemia after the diagnosis of PNH. However, elevated serum glucose (random), fructosamine, and glycated albumin suggest ongoing hyperglycemia. Together, these results argue that the decline in hemoglobin A1c was due to decreased RBC survival secondary to PNH.
Conclusions:
Hemoglobin A1c levels must be interpreted with caution in patients with hematologic diseases that change RBC survival. Serum fructosamine and glycated albumin measurements are alternative measures of time-averaged blood glucose control and may be useful in this subset of patients.
More Related Videos
Related Concept Videos
Hyperglycemia
Oxygen Transport in the Blood
Hypoglycemia
Hemoglobin
When all four heme groups are bound to oxygen, the resulting molecule is called oxyhemoglobin. As a result, arterial blood...
Type II Diabetes Mellitus III: Clinical Manifestations and Diagnosis

