Can a Blood Test Detect Cancer? Understanding the Science

At Chelsea Green Pharmacy, we’re often asked by patients whether a simple blood test can detect cancer. It’s an important and complex question—and one that science is increasingly beginning to answer. While not all cancers can be identified through blood alone, there are certain types that do produce measurable changes in the blood, and modern testing is now more sophisticated than ever.

If you’ve found yourself searching “can a blood test detect cancer”, this article will explain what blood tests can reveal, how they work, and when it may be worth booking one, especially as part of a proactive approach to your health.

How Can Blood Tests Help Detect Cancer?

Blood tests are a powerful tool in assessing your overall health, but when it comes to cancer, they offer more than just general insight. In some cases, specific biological markers—known as tumour markers—can be detected in the blood, indicating the presence of certain cancers.

There are also newer technologies, such as circulating tumour DNA (ctDNA) testing, which can pick up fragments of genetic material shed by cancerous tumours into the bloodstream. These tests are increasingly being used in advanced diagnostics and monitoring, although they are not yet standard for all types of cancer.

In addition to these more specialised methods, general abnormalities in routine blood tests—such as changes in white blood cell counts, liver function, or levels of certain proteins—can sometimes raise red flags that lead to further investigation.

What Are Tumour Markers?

Tumour markers are substances—often proteins—produced by cancer cells or by the body in response to cancer. These markers can sometimes be detected in higher-than-normal amounts in the blood. Examples include:

• PSA (Prostate-Specific Antigen) for prostate cancer

• CA-125 for ovarian cancer

• CEA (Carcinoembryonic Antigen) for bowel and some lung cancers

• AFP (Alpha-Fetoprotein) for liver or testicular cancer

• hCG for certain testicular and ovarian cancers

It’s important to note, however, that tumour markers are not definitive diagnostic tools. They can be raised for non-cancerous reasons, and not all cancers produce them in detectable amounts. Instead, they are typically used as part of a wider diagnostic process or for monitoring treatment response.

Which Cancers Can Be Detected Through Blood Tests?

While a blood test can’t detect all cancers, certain types are more reliably identified through blood-based markers or abnormalities:

Cancers that can potentially be detected through blood tests:

• Leukaemia (via full blood count and blast cell presence)

• Lymphoma (elevated white cell counts, LDH levels)

• Multiple myeloma (abnormal protein levels)

• Prostate cancer (raised PSA)

• Ovarian cancer (elevated CA-125)

• Liver cancer (high AFP levels)

• Testicular cancer (hCG and AFP)

• Colorectal cancer (CEA levels, in advanced stages)

Cancers that usually can’t be detected through blood tests alone:

• Breast cancer

• Lung cancer (except sometimes via CEA or NSE markers)

• Pancreatic cancer

• Kidney cancer

• Skin cancers (e.g. melanoma)

• Brain tumours

In these cases, imaging and biopsy remain the gold standard for diagnosis. However, blood tests may still play a role in overall assessment and monitoring.

Introducing Our Male and Female Cancer Blood Test Services

At Chelsea Green Pharmacy, we offer comprehensive cancer screening blood tests designed to support early detection and peace of mind.

Our Female Cancer Blood Test screens for a range of tumour markers, including CA-125, CEA, and others relevant to ovarian, uterine, and gastrointestinal cancers.

Our Male Cancer Blood Test includes markers such as PSA, AFP, CEA, and hCG, commonly associated with prostate, testicular, and bowel cancers.

These tests are particularly suitable for individuals with:

• A family history of cancer

• Persistent symptoms that remain unexplained

• A desire for routine private screening

• A history of cancer and a need for regular monitoring

Results are usually available within a few days, and we offer follow-up support to help you interpret your results and plan any necessary next steps.

The Importance of a Clinical Approach

While blood tests are useful, it’s crucial to view them as part of a broader picture. They are not a replacement for medical imaging, physical examinations, or biopsy in suspected cancer cases. A raised tumour marker alone does not mean you have cancer, just as normal results do not always rule it out.

That’s why at Chelsea Green Pharmacy, we combine clinical expertise with access to private testing, helping you make informed decisions about your health.

Book Your Cancer Blood Test Today

If you’ve been wondering can a blood test detect cancer, the answer is: in some cases, yes—and in others, it can offer early indicators worth following up.

Our private blood testing services are fast, confidential, and carried out with the highest standards of care. Whether you’re experiencing symptoms, monitoring an existing condition, or simply being proactive, we’re here to support you. Reach out today to find out more.

Alternatively, book your appointment with Chelsea Green Pharmacy today and take a confident step towards understanding your health.