Can a CBC Be Ordered Under Hypertension?
Yes, a Complete Blood Count (CBC) is explicitly recommended as part of the routine laboratory evaluation for all patients with hypertension.
Guideline-Based Recommendations
Standard Initial Laboratory Testing
The major hypertension guidelines consistently include CBC (specifically hemoglobin and/or hematocrit) as part of routine testing:
The 2013 ESH/ESC Guidelines explicitly list "Haemoglobin and/or haematocrit" as a routine test for all hypertensive patients 1
The 2024 ESC Guidelines recommend measuring serum creatinine, eGFR, and urine ACR in all patients with hypertension, with ECG as standard testing 1, though they focus more on renal and cardiac markers in their abbreviated list
The American College of Cardiology recommends ordering a complete blood count as part of the comprehensive metabolic evaluation for hypertensive patients 2
Clinical Rationale for CBC in Hypertension
The CBC serves multiple important purposes in hypertensive patients:
Detects anemia or other hematologic abnormalities that may affect cardiovascular risk stratification 2
Provides baseline hematologic values before initiating antihypertensive therapy 3
Helps identify secondary causes of hypertension or comorbid conditions 1, 3
White blood cell count and related parameters (like neutrophil-to-lymphocyte ratio) can predict cardiovascular disease risk 4
Special Populations
Pregnancy-Related Hypertension
For women with chronic hypertension in pregnancy, a full blood count (hemoglobin and platelet count) is explicitly recommended at first diagnosis to establish baseline values 1. This becomes critical for detecting superimposed preeclampsia, which complicates up to 25% of these pregnancies 1.
Comprehensive Initial Workup
The complete routine laboratory panel for hypertension typically includes 1, 2, 5:
- Hemoglobin and/or hematocrit (CBC)
- Fasting plasma glucose
- Lipid profile (total cholesterol, LDL, HDL, triglycerides)
- Serum electrolytes (sodium, potassium)
- Serum creatinine with eGFR
- Uric acid
- Urinalysis with albumin-to-creatinine ratio
- 12-lead ECG
Clinical Pitfalls to Avoid
Do not skip the CBC thinking it's unnecessary for hypertension - it is part of standard guideline-recommended testing 1, 2
Do not delay basic laboratory testing once hypertension is confirmed - the initial evaluation should be comprehensive to detect target organ damage and assess cardiovascular risk 2, 3
Remember that CBC abnormalities may provide clues to secondary causes of hypertension (e.g., polycythemia in sleep apnea, anemia in renal disease) 1, 3
Billing and Documentation
From a practical standpoint, ordering a CBC under the diagnosis of hypertension is medically appropriate and justified based on established clinical guidelines 1, 2. The test is part of the standard initial evaluation to assess for target organ damage, detect comorbidities, and establish baseline values before treatment 3, 6.