You've just received orders for routine blood work, and you notice "CBC" listed among the tests. Perhaps you're concerned about your liver or kidney health and wondering if this test will provide the answers you need. Approximately 7 billion CBC tests are performed worldwide each year, making it one of the most common diagnostic procedures, but does it actually evaluate your liver and kidney function?

Understanding what a CBC can and cannot tell you about your organ health is crucial for making informed healthcare decisions. Although CBC results may offer some indirect clues about liver and kidney status, they don't provide the comprehensive organ function data many patients expect.

Understanding Complete Blood Count (CBC) Tests

A Complete Blood Count (CBC) is a fundamental blood test that provides a broad overview of your blood components and general health status. According to the American Society of Hematology, approximately 450 million CBC tests are performed annually in the United States alone, making it the most frequently ordered laboratory test in medicine.

A CBC analyzes the three main components of your blood:

1. Red Blood Cells (RBCs): These oxygen-carrying cells are measured for quantity (RBC count), quality (size and shape), and oxygen-carrying capacity (hemoglobin and hematocrit).

2. White Blood Cells (WBCs): Your immune system's primary defenders are counted both in total and by specific type (neutrophils, lymphocytes, monocytes, eosinophils, and basophils).

3. Platelets: These cell fragments are essential for blood clotting and preventing excessive bleeding.

A standard CBC report typically includes:

• Red blood cell count (RBC)

• Hemoglobin (Hgb)

• Hematocrit (Hct)

• Red blood cell indices (MCV, MCH, MCHC, RDW)

• White blood cell count (WBC) with differential

• Platelet count

According to the National Institutes of Health, CBCs are ordered in approximately 85% of initial patient evaluations, serving as a crucial screening tool that helps healthcare providers identify a wide range of conditions from infections to blood disorders.

The Direct Answer: CBC's Relationship to Organ Function

For those seeking a straightforward answer: No, a CBC does not directly measure liver or kidney function. This common misconception leads many patients to believe they've received comprehensive organ screening when they haven't.

CBC tests are not designed to:

• Measure liver enzymes that indicate liver damage or disease

• Assess kidney filtration rates or waste product levels

• Detect early-stage liver or kidney dysfunction

• Evaluate the specific metabolic functions of these organs

However, CBC results do sometimes provide indirect clues that might suggest further investigation is needed. 

Potential Liver Function Indicators in CBC Results

While a CBC doesn't directly measure liver function, certain abnormalities might indirectly suggest liver issues:

The liver plays a crucial role in red blood cell production and regulation. According to research published in Hepatology, approximately 75% of patients with advanced liver disease show some form of red blood cell abnormality on their CBC results:

• Macrocytosis: Enlarged red blood cells (high MCV) may occur in liver disease, especially alcoholic liver disease.

• Anemia: Low red blood cell counts or hemoglobin levels are present in approximately 65 to 75% of patients with chronic liver disease.

The relationship between platelets and liver health is particularly significant:

• Thrombocytopenia: Low platelet counts occur in up to 70% of patients with cirrhosis due to splenic sequestration and decreased production of thrombopoietin, a hormone primarily produced by the liver.

• Studies show that platelet counts under 150,000/μL have a sensitivity of approximately 80% for detecting portal hypertension in liver disease patients.

Certain white blood cell patterns might suggest liver inflammation or infection:

• Neutrophilia: An elevated neutrophil count might indicate alcoholic hepatitis or acute liver inflammation.

• Lymphocytosis: Increased lymphocytes may suggest viral hepatitis.

Learn more in this comprehensive guide to at-home liver tests.

Potential Kidney Function Clues in CBC Results

Like the liver, kidney problems may sometimes be suggested by CBC abnormalities, though not definitively diagnosed:

The strongest kidney-related CBC finding is anemia:

• According to the National Kidney Foundation, anemia occurs in more than 40% of patients with chronic kidney disease (CKD).

• The kidneys produce erythropoietin, a hormone that stimulates red blood cell production. When kidney function declines, erythropoietin production decreases, potentially leading to anemia.

• Studies show that hemoglobin levels below 12 g/dL in CKD patients correlate with a higher risk of disease progression.

For more details, see this comprehensive guide on understanding creatinine levels.

Kidney dysfunction can affect red blood cell shape and size:

• Burr cells (echinocytes) or fragmented red cells (schistocytes) may appear on blood smears in advanced kidney disease.

• Research published in the American Journal of Kidney Diseases found that approximately 35% of end-stage renal disease patients show abnormal red blood cell morphology.

White blood cell patterns can also provide clues:

• Leukocytosis: Elevated white blood cell counts may suggest kidney infection (pyelonephritis).

• Neutrophilia: Increased neutrophils often accompany kidney infections or inflammation.

A study analyzing data from the National Health and Nutrition Examination Survey (NHANES) found that the prevalence of anemia increases with the severity of CKD, affecting approximately 15.4% of individuals with stage 1–2 CKD and up to 53.4% in stage 4–5 CKD .

Learn what causes protein in urine and how to interpret test results.

Tests That Actually Measure Liver Function

To properly assess liver function, healthcare providers order specific liver function tests (LFTs) that directly measure liver enzymes, proteins, and metabolic products:

These enzymes leak into the bloodstream when liver cells are damaged:

• Alanine Aminotransferase (ALT): Primarily found in the liver; elevated levels are approximately 90% specific for liver damage.

• Aspartate Aminotransferase (AST): Found in the liver and other tissues; elevations may suggest liver injury but are less specific.

• Alkaline Phosphatase (ALP): Can indicate bile duct obstruction when elevated.

• Gamma-Glutamyl Transferase (GGT): Often rises with alcohol consumption and certain liver diseases.

Uncover early signs of liver disease and the benefits of timely testing.

It is estimated that 1% to 9% of asymptomatic individuals have elevated liver enzyme levels when screened using standard liver function tests.

Other important liver function indicators include:

• Bilirubin: Elevated levels cause jaundice; direct bilirubin suggests the liver cannot properly process this waste product.

• Albumin: This protein, produced by the liver, decreases in chronic liver disease. Research shows that albumin levels below 3.5 g/dL correlate with a reduction in five-year survival rates in cirrhosis patients.

• Prothrombin Time (PT)/International Normalized Ratio (INR): The liver produces clotting factors; when impaired, these values increase, indicating decreased liver synthetic function.

Learn more in this comprehensive guide to at-home liver tests.

Tests That Actually Measure Kidney Function

For accurate kidney function assessment, specific kidney tests are required:

Key kidney function markers include:

• Blood Urea Nitrogen (BUN): This waste product increases when kidneys aren't filtering properly.

• Creatinine: A muscle breakdown product that healthy kidneys filter efficiently. According to the National Kidney Foundation, a creatinine level above 1.2 mg/dL for women or 1.4 mg/dL for men warrants further kidney evaluation.

The most important kidney function measurement is:

• eGFR (estimated GFR): Calculated from creatinine levels, age, gender, and race, this provides the most accurate assessment of kidney function.

• An eGFR below 60 mL/min/1.73m² for three or more months indicates chronic kidney disease.

• Research shows that approximately 37 million Americans (15% of adults) have chronic kidney disease, but only 10% are aware of their condition, highlighting the importance of proper testing.

Other important kidney function indicators include:

• Electrolytes: Sodium, potassium, chloride, and bicarbonate levels may indicate kidney dysfunction.

• Urinalysis: Detecting protein, blood, or abnormal specific gravity in urine can reveal kidney problems.

Discover the impact of at-home kidney tests for better long-term care.

When to Request Comprehensive Blood Testing

Knowing when to ask your healthcare provider for liver or kidney function tests beyond a standard CBC is essential for early detection of potential problems.

You should request liver function tests if you experience:

• Yellowing of skin or eyes (jaundice)

• Abdominal pain or swelling, particularly in the upper right quadrant

• Dark urine or light-colored stools

• Chronic fatigue or unexplained weight loss

• Nausea or lack of appetite

Uncover early signs of liver disease and the benefits of timely testing.

A study published in BMJ Open introduced the CIRRUS algorithm, which analyzes standard blood tests to identify liver cirrhosis. The algorithm was able to detect over 70% of individuals with cirrhosis months or years before their first emergency hospital admission. This highlights the potential of routine blood tests in identifying liver disease before symptoms appear

Consider asking for kidney function tests if you have:

• Swelling in feet, ankles, or around the eyes

• Foamy or bloody urine

• Difficulty urinating or changes in urination patterns

• Persistent fatigue or shortness of breath

• High blood pressure that's difficult to control

According to the American Kidney Fund, early detection through appropriate testing can slow kidney disease progression by up to 70% in many cases.

You should discuss regular liver and kidney function monitoring with your healthcare provider if you have:

• Diabetes (affects approximately 10.5% of Americans)

• Hypertension (affects approximately 47% of American adults)

• Family history of liver or kidney disease

• History of alcohol misuse

• Obesity (affects approximately 42% of American adults)

• Certain medications that can affect liver or kidney function

Read our guide to at-home urine protein test kits for more on kidney health tracking.

How to Interpret Your Blood Test Results

Understanding your test results empowers you to take an active role in your health management:

Normal vs. abnormal values:

• Reference ranges: These vary slightly between laboratories but provide guidelines for what's considered normal.

• Marginally abnormal results: May require monitoring rather than immediate intervention. 

• Significantly abnormal results: Usually warrant further investigation or treatment.

Find out how blood sugar test kits can help monitor your body's overall status.

The importance of trends:

• Single abnormal results are less concerning than persistent or worsening patterns.

• Tracking trends in test results over time improves diagnostic accuracy by approximately compared to single measurements.

• Keep records of your test results to help identify changes over time.

When discussing test results, consider asking:

• "How do my current results compare to previous ones?"

• "Do any of these results suggest liver or kidney concerns?"

• "Should I have additional testing based on these results?"

• "How often should I have my liver or kidney function tested?"

Comprehensive Metabolic Panel: The Better Option

For those concerned about liver and kidney health, a Comprehensive Metabolic Panel (CMP) offers a more complete assessment:

A standard CMP measures:

• Glucose

• Electrolytes (sodium, potassium, chloride, bicarbonate)

• Calcium

• Kidney function tests (BUN, creatinine) - Read more on creatinine levels for stage 3 kidney disease 

• Liver function tests (ALT, AST, ALP, bilirubin)

• Total protein and albumin

Approximately 200 million CMP tests are performed annually in the United States, offering a more comprehensive assessment of organ function than Complete Blood Count (CBC) tests alone. 

Cost and coverage:

• The average cost of a CMP ranges from $35 to $85 when paying out of pocket.

• Most insurance plans cover CMP testing once yearly for preventive care.

• Studies show that early detection through appropriate testing is approximately 4-6 times more cost-effective than treating advanced organ disease.

Most physicians order both CBC and CMP for routine health screenings:

• This combination provides most of the information needed for a general health assessment.

• A survey published in JAMA Internal Medicine found that 39% of primary care physicians reported routinely ordering a CBC as part of an annual physical examination.

You can also explore how fasting glucose levels relate to overall metabolic and organ health.

At-Home Testing Options

For those seeking convenient monitoring options:

Available self-testing kits include:

• Liver function test kits: Typically measure ALT, AST, and sometimes additional markers.

• Kidney function test kits: Usually measure creatinine, BUN, and sometimes estimate GFR.

• Combined organ function tests: More comprehensive options that assess multiple organ systems.

At-home testing may be suitable for:

• Monitoring known conditions between doctor visits

• Initial screening before deciding to seek medical care

• Those with risk factors who want more frequent monitoring

However, at-home tests should complement, not replace, clinical testing. According to healthcare utilization studies, patients who use at-home testing visit their physicians more regularly than those who don't, suggesting improved health engagement.

The Bottom Line

While a CBC provides valuable health information, it does not directly measure liver or kidney function. For comprehensive organ assessment, specific tests are required:

• Liver function requires measurement of enzymes (ALT, AST, ALP), proteins (albumin), and metabolic products (bilirubin).

• Kidney function requires assessment of filtration markers (BUN, creatinine, eGFR) and often urinalysis.

Understanding these distinctions helps you advocate for appropriate testing based on your symptoms, risk factors, and health concerns. For those with risk factors for liver or kidney disease, discussing a comprehensive testing approach with your healthcare provider is essential. 

For those with risk factors, early detection is key. Ribbon Checkup offers a quick, at-home urine test that screens for multiple markers, enabling you to take charge of your health.

Take a step towards proactive health management. Learn more at ribboncheckup.com.

Related Resources

• The Complete Guide to At-Home Kidney Function Tests

• Anemia and Liver Disease

• What Is the Creatinine Level for Stage 3 Kidney Disease?

• Fatty Liver Symptoms on Face: A Comprehensive Guide

Written by Abel Tamirat, MD
Dr. Abel Tamirat is a licensed General Practitioner and ECFMG-certified international medical graduate with over three years of experience supporting U.S.-based telehealth and primary care practices. As a freelance medical writer and Virtual Clinical Support Specialist, he blends frontline clinical expertise with a passion for health technology and evidence-based content. He is also a contributor to Continuing Medical Education (CME) programs.

References

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Geng, C. (2022, October 6). What to know about a basic metabolic panel (BMP). Retrieved May 10, 2025, from Medicalnewstoday.com website: https://www.medicalnewstoday.com/articles/bmp 

Qamar, A. A., & Grace, N. D. (2009). Abnormal Hematological Indices in Cirrhosis. Canadian Journal of Gastroenterology, 23(6), 441–445. https://doi.org/10.1155/2009/591317 

Santo, L., M, S. S., & Ashman, J. (2022). Characteristics of Visits to Health Centers, 2020. https://doi.org/10.15620/cdc:117898 

Schweitzer, S. O. (2025). Cost Effectiveness of Early Detection of Disease. Health Services Research, 9(1), 22. Retrieved from https://pmc.ncbi.nlm.nih.gov/articles/PMC1071777/ 

Stauffer, M. E., & Fan, T. (2014). Prevalence of Anemia in Chronic Kidney Disease in the United States. PLoS ONE, 9(1), e84943–e84943. https://doi.org/10.1371/journal.pone.0084943