Understanding Blood Test Request Abbreviations
Blood test request forms use standardized abbreviations to communicate which laboratory tests should be performed, with the most common being CBC (Complete Blood Count), which provides comprehensive information about red blood cells, white blood cells, and platelets. 1, 2
Common Blood Test Abbreviations
Complete Blood Count (CBC) Components
CBC with Differential is the foundational hematologic test that includes multiple parameters 1, 2:
- WBC = White Blood Cell count (total leukocyte count) 3, 1
- RBC = Red Blood Cell count 1
- Hgb or Hb = Hemoglobin (oxygen-carrying protein) 1
- Hct = Hematocrit (percentage of blood volume occupied by red cells) 1
- MCV = Mean Corpuscular Volume (average red blood cell size) 1, 2
- Plt = Platelet count 3, 1
- Diff = Differential (breakdown of white blood cell types by percentage and absolute count) 3, 1
- Retic = Reticulocyte count (immature red blood cells) 3, 1
White Blood Cell Differential Components
The differential breaks down into specific cell types 3, 1:
- Neu or PMN = Neutrophils (bacterial infection fighters) 3, 1
- Lym = Lymphocytes (viral immunity and immune regulation) 3, 1
- Mono = Monocytes 1
- Eos = Eosinophils (allergic and parasitic responses) 3, 1
- Baso = Basophils 1
Hepatitis and Liver Testing Abbreviations
HBsAg = Hepatitis B surface Antigen (indicates active HBV infection) 3, 4
HBsAb = Hepatitis B surface Antibody (indicates immunity to HBV) 3, 4
HBcAb = Hepatitis B core Antibody (indicates past or current HBV infection) 3
HCV = Hepatitis C Virus antibody or RNA testing 3
Other Common Abbreviations
BUN = Blood Urea Nitrogen (kidney function) 3
Cr or Creat = Creatinine (kidney function) 3
ALT = Alanine Aminotransferase (liver enzyme) 3
AST = Aspartate Aminotransferase (liver enzyme) 3
Alk Phos = Alkaline Phosphatase (liver/bone enzyme) 3
TSH = Thyroid Stimulating Hormone 2
INR = International Normalized Ratio (blood clotting measure) 3
Critical Pitfall to Avoid
The abbreviations HBsAb and HBsAg are frequently confused during transcription, with studies showing this specific error occurring in approximately 15% of transcription mistakes involving hepatitis testing. 4 These represent completely different tests—one indicates immunity (HBsAb) while the other indicates active infection (HBsAg)—making this confusion clinically dangerous 3, 4.
Reporting Standards
Both percentages AND absolute counts should be reported for white blood cell differential results, as absolute counts provide more clinically meaningful information than percentages alone. 3, 1 For example, a lymphocyte percentage of 20% could represent normal absolute lymphocyte count in one patient but severe lymphopenia in another depending on the total WBC 3, 1.
When Results Should Include Additional Detail
Manual blood smear review with morphology description should accompany automated CBC results when there are unexplained cytopenias, concern for hematologic malignancy, or significant abnormalities detected by automated analyzers. 3, 2 Automated parameters alone may miss critical findings like blasts, dysplastic changes, or schistocytes that require urgent intervention 2.