Can Kidney Cancer Be Detected in a Blood Test?

Understanding the role of blood tests and other diagnostic tools in the early detection and evaluation of kidney cancer symptoms.

By Sneha Tete, Integrated MA, Certified Relationship Coach

Created on Sep 26, 2025

Understanding the role of blood tests and other diagnostic tools in the early detection and evaluation of kidney cancer symptoms.

Kidney cancer, also known as renal cell carcinoma, is one of the most common cancers affecting the urinary system. Early detection improves the odds of successful treatment, and many patients wonder whether a simple blood test is sufficient to detect this type of cancer. This article examines the limitations and potential of blood tests for kidney cancer detection, additional diagnostic tools, warning symptoms, and when to seek medical advice.

About Blood Tests and Kidney Cancer

Blood tests are a foundational tool in evaluating health and organ function, but they have significant limitations when it comes to diagnosing cancer—especially kidney cancer. In fact, a blood test alone cannot diagnose kidney cancer; rather, blood tests provide important clues that may point to kidney dysfunction or an underlying problem that requires further testing.

Blood tests, including complete blood counts and blood chemistry panels, are often part of routine health screenings. Results outside the normal range can signal that something is wrong, possibly triggering additional investigations such as imaging studies.

Blood tests cannot directly identify kidney cancer cells.
Abnormal blood work may suggest kidney dysfunction or other issues that require diagnostic imaging.
Blood work helps guide the next steps in the diagnostic process, but cannot confirm or rule out kidney cancer by itself.

Why Are Blood Tests Important?

While they can’t confirm cancer, blood tests serve three key functions in the context of kidney health:

Evaluating overall kidney function.
Checking for potential complications or associated medical conditions (such as anemia).
Guiding physicians toward more specific diagnostic procedures if abnormal results are found.

Key Blood Tests Used in Kidney Cancer Evaluation

Although they don’t diagnose kidney cancer, several blood tests are regularly used to assess kidney function and identify the need for further evaluation.

1. Complete Blood Count (CBC)

A CBC measures different types of cells in your blood, including red blood cells (RBCs), white blood cells (WBCs), and platelets. In patients with kidney cancer, the following anomalies may be seen:

Anemia: Lower than normal red blood cell count is common in those with kidney cancer, reflecting poor kidney function or effects from the cancer itself.
Polycythemia: In rare cases, kidney cancer may trigger the release of excess erythropoietin, resulting in too many red blood cells.

2. Basic Metabolic Panel (BMP)

The basic metabolic panel tests levels of important compounds, including electrolytes, minerals, and metabolic byproducts. Specific results that may be relevant in kidney cancer include:

High calcium levels (hypercalcemia), which can be associated with kidney cancer.
Abnormal blood urea nitrogen (BUN) and creatinine—indicators of compromised kidney function.
Elevated liver enzymes, which may indicate cancer that has spread or other underlying issues.

3. Serum Creatinine

Creatinine is a waste product excreted by healthy kidneys. Elevated levels in the blood can point to reduced kidney function, but do not diagnose cancer specifically. Measurement of serum creatinine is used to estimate the glomerular filtration rate (GFR), a key indicator of kidney health.

Blood Test Results That May Indicate a Kidney Problem

Certain blood test results indicate your kidneys may not be functioning properly, which could prompt further diagnostic tests:

Evidence of anemia (low red blood cells) or, less commonly, polycythemia (high red blood cells).
Abnormal blood chemistry: elevated calcium or liver enzymes.
High levels of creatinine or BUN, suggesting chronic kidney damage or disease.

It’s important to remember that these abnormalities do not constitute a diagnosis of kidney cancer; they simply suggest that further investigation, including imaging and possibly biopsy, is required.

What Tests Are Most Often Used to Diagnose Kidney Cancer?

If your physician suspects kidney cancer based on symptoms or abnormal blood work, a more comprehensive and definitive diagnostic process is required. The most commonly used tests include:

Imaging Tests: Identify potential tumors, help distinguish between benign and malignant growths, and determine cancer staging.
Urine Tests: Useful for detecting blood, abnormal cells, or proteins associated with kidney dysfunction or cancer.
Biopsy: In select cases, a tissue sample is examined under a microscope to confirm cancer.

Imaging Tests in Kidney Cancer Diagnosis

Test	Description	What It Shows
CT Scan	Uses X-rays and computer processing to produce detailed cross-sectional images of your kidneys. May require contrast material for enhanced imaging.	Helpful for detecting tumors, defining their size/location, and checking if the cancer has spread. May also provide clues as to whether a tumor is likely cancerous.
MRI	Uses powerful magnets and radio waves to create detailed images without radiation.	Useful for patients who can’t tolerate CT contrast agents, clarifies involvement of blood vessels and differentiates between benign and malignant growths.
Ultrasound	Employs sound waves to create images of the kidneys and distinguish between fluid-filled cysts and solid masses.	Helpful for the initial evaluation of suspicious kidney areas or masses.
Intravenous Pyelogram (IVP)	Injects contrast dye for X-ray visualization of kidneys, ureters, and bladder.	Can identify abnormalities, tumors, or blockages in the urinary system.
Angiography	Contrast dye injected to examine kidney blood vessels, sometimes as part of CT or MRI.	Helps map blood supply to tumors and assesses potential for surgical removal.

Can Any Blood Test Directly Diagnose Kidney Cancer?

Although some promising research is underway, as of now, no routine blood test alone can directly diagnose kidney cancer. Blood work may indicate kidney dysfunction or flag issues needing more evaluation, but confirmation depends on other modalities.

New techniques, such as liquid biopsies (which analyze blood for cancer-related biomarkers), are showing potential for the future. Recent studies using experimental biomarker panels report extremely high accuracy in distinguishing patients with kidney cancer from healthy individuals, especially with blood-based samples. However, these methods are not yet widely available for standard clinical care.

Symptoms of Kidney Cancer

One of the most challenging features of kidney cancer is its tendency to produce no symptoms in the early stages. Many cases are discovered incidentally on imaging done for unrelated reasons, or after abnormalities are seen in routine blood work.

Possible warning signs of kidney cancer include:

Blood in the urine (hematuria)
Persistent lower back or flank pain
Unexplained weight loss
Fever not linked to an infection
Extreme fatigue
Loss of appetite
Anemia (may show up first on blood tests)
High blood pressure (hypertension)
Swelling in the legs or ankles
Abdominal mass (in advanced cases)

Many of these symptoms can result from conditions other than kidney cancer. However, persistent or severe symptoms always warrant medical evaluation.

When to Seek Medical Care

Because symptoms are often absent or nonspecific, early kidney cancer can be hard to catch without routine exams. However, you should contact your healthcare provider promptly if you experience:

Visible blood in your urine or persistent pinkish discoloration
Unexplained lower back or flank pain that doesn’t resolve
Unexplained and unintentional weight loss
Persistent fatigue, fever, or significant changes in blood test results

Early evaluation increases the likelihood that a problem can be identified and addressed before it progresses.

Frequently Asked Questions (FAQs)

Can a blood test alone tell me if I have kidney cancer?

No. While blood tests may suggest kidney problems or complications, they cannot detect kidney cancer on their own. Further evaluation, including imaging and possibly a biopsy, is required for diagnosis.

What does it mean if my blood test shows high calcium or anemia?

High calcium or low hemoglobin/anemia may indicate kidney dysfunction, which could be related to cancer or another kidney disorder. These results are a signal for additional diagnostic steps, not a confirmation of cancer.

What other diagnostic tools are most reliable for kidney cancer?

Imaging studies (such as CT scans, MRIs, and ultrasounds) are the gold standard for detecting and evaluating kidney cancer. Blood work and urine tests provide important supporting information.

What new tests or research are on the horizon?

Researchers are working on novel blood-based biomarkers and liquid biopsy techniques with high accuracy for detecting even early-stage kidney cancers. These could supplement or eventually transform the current diagnostic process if widely validated and adopted.

Should everyone get imaging tests for kidney cancer?

No. Imaging is recommended for those with persistent symptoms or abnormal blood/urine test results. Routine imaging for everyone without symptoms or risk factors is not generally advised.

Key Takeaways

Blood tests cannot diagnose kidney cancer on their own. They provide crucial information about kidney function and guide whether further testing is needed.
Imaging studies such as CT, MRI, and ultrasound are the mainstays for detecting and diagnosing kidney cancer.
Symptoms are often absent early on; regular checkups and follow-up of abnormal results are essential for early detection.
Blood-based biomarker detection (liquid biopsies) is an evolving field showing promising results for the future, but not yet a routine clinical tool.

Further Resources

National Cancer Institute: Kidney Cancer—Patient Version
American Cancer Society: Kidney Cancer
Research articles on liquid biopsy and biomarker discovery

References

Author

Sneha TeteBeauty & Lifestyle Writer

Sneha is a relationships and lifestyle writer with a strong foundation in applied linguistics and certified training in relationship coaching. She brings over five years of writing experience to thebridalbox, crafting thoughtful, research-driven content that empowers readers to build healthier relationships, boost emotional well-being, and embrace holistic living.

Read full bio of Sneha Tete