ICD-10 Codes for Ordering Labs in Anemia with Impaired Fasting Glucose
For a patient with anemia and impaired fasting glucose, use ICD-10 code D64.9 (anemia, unspecified) or a more specific anemia code if known, combined with R73.01 (impaired fasting glucose) to justify ordering both complete blood count and glucose-related laboratory tests.
Primary Diagnostic Codes
For Anemia
- D64.9 - Anemia, unspecified (if specific type unknown)
- D50.9 - Iron deficiency anemia, unspecified (if iron deficiency suspected)
- D63.8 - Anemia in other chronic diseases (if associated with metabolic conditions)
The specific anemia code should be selected based on clinical presentation, as iron-deficiency anemia can falsely elevate HbA1c results 1.
For Impaired Fasting Glucose
- R73.01 - Impaired fasting glucose (IFG)
- R73.03 - Prediabetes (alternative broader code)
Impaired fasting glucose is defined as fasting plasma glucose 100-125 mg/dL (5.6-6.9 mmol/L) 1, 2.
Laboratory Tests Justified by These Codes
Anemia Workup
- Complete blood count (CBC) with differential
- Mean corpuscular volume (MCV)
- Mean corpuscular hemoglobin (MCH)
- Serum iron studies
- Ferritin
- Reticulocyte count
These tests are essential because anemia affects red blood cell turnover, which directly impacts the accuracy of HbA1c testing 1.
Glucose Metabolism Assessment
- Fasting plasma glucose - Should be drawn in the morning after at least 8 hours of fasting 1
- HbA1c - Use with caution in this patient due to anemia
Critical caveat: In patients with anemia, HbA1c measurements may provide spurious (generally falsely low or falsely high depending on type) results regardless of the method used 1. Iron-deficiency anemia specifically is reported to falsely increase HbA1c results 1.
Alternative Glycemic Markers (if needed)
If anemia significantly affects red blood cell turnover, consider ordering:
- Fructosamine or glycated albumin - These reflect shorter periods of average glycemia and are not affected by red blood cell abnormalities 1
Use code R73.01 or R73.03 to justify these alternative glycemic markers when HbA1c interpretation is compromised 1.
Important Clinical Considerations
Timing and Sample Handling
- Blood for fasting plasma glucose must be collected after overnight fast (minimum 8 hours) 1
- Samples should be placed in tubes with citrate buffer and centrifuged within 15-30 minutes to prevent glycolysis 1
- Sodium fluoride tubes alone are insufficient to prevent glycolysis 1
Diagnostic Confirmation
- Diagnosis of impaired fasting glucose should be confirmed with repeated testing on a different day 1
- If using two different tests (such as fasting glucose and HbA1c), both results above diagnostic thresholds confirm the diagnosis 1
When to Avoid HbA1c
Do not rely on HbA1c alone for diagnosis or monitoring in this patient because conditions that affect red blood cell turnover (including anemia) compromise HbA1c interpretation 1. Plasma glucose criteria should be used instead 1.
Additional Codes to Consider
If further evaluation reveals:
- E11.9 - Type 2 diabetes mellitus without complications (if glucose progresses to diabetic range)
- D50.0 - Iron deficiency anemia secondary to blood loss (if applicable)
- E78.5 - Hyperlipidemia, unspecified (commonly coexists with impaired fasting glucose) 2, 3
Screening Interval
For patients with initial impaired fasting glucose, repeat testing should occur at 3-year intervals if values normalize 1.