How Accurate Are Blood Tests for Cancer Detection?

Introduction

One of the most asked questions is can a bone profile blood test detect cancer? Take a look at this blog to find out if blood tests are appropriate for detecting cancer.

Cancer blood tests help healthcare providers diagnose and stage malignancies (cancerous growths) by offering insights into overall health, organ function, and potential disease. While valuable, these tests alone are not enough for a complete diagnosis; additional tests are typically required to develop a detailed understanding of its condition and progression.

Can blood test detect cancer?

Blood tests are an important tool for diagnosing, staging, and managing cancer, but they are rarely sufficient for an official diagnosis. While blood work alone cannot detect most cancers, it can help identify specific blood cancers such as Hodgkin lymphoma, non-Hodgkin lymphoma, leukaemia, and multiple myeloma. Additional diagnostic tests are typically required to confirm the presence and type of cancer.

Types of Blood Test for Cancer Detection

Healthcare providers classify cancer blood tests into four primary categories:

1. Complete Blood Count (CBC)
   
   A CBC measures different components of your blood and can help detect cancers of the blood or immune system, such as lymphoma and leukemia. However, it is not effective for diagnosing solid organ cancers like breast, lung, or colon cancer. A CBC can also provide information about how your body responds to treatment and whether cancer has spread to your bone marrow.
   
   
2. Tumour Marker Blood Tests
   
   These tests measure specific chemicals in the blood that might indicate cancer. Elevated levels of these markers can suggest the presence of cancer. For example, the CA-125 test is commonly used to detect and monitor ovarian and pancreatic cancers, as well as check for their recurrent outbreaks. Another example is the PSA (prostate-specific antigen) test, which measures PSA levels in the blood. PSA is a protein produced by the prostate, and high levels may indicate prostate cancer.
   
   
3. Blood Protein Tests
   
   These tests identify abnormal levels of proteins in your blood, which can indicate blood cancers like leukaemia, lymphoma, or multiple myeloma. A comprehensive metabolic panel (CMP), which often includes a total protein test, can also help identify these abnormalities. Persistent or significantly elevated protein levels require further investigation.
   
   
4. Circulating Tumour Cell (CTC) Tests:
   
   CTC tests are a form of liquid biopsy that detects fragments of tumours circulating in the bloodstream. These tests are particularly useful for monitoring metastatic cancers such as breast, prostate, and colon cancer. A low or undetectable level of CTCs often indicates a favourable prognosis, while high levels might signify a poor outcome or the need for additional treatment.

Each of these blood tests serves a unique role in cancer diagnosis, staging, and management, but they are often used in combination with other diagnostic tools for a complete picture of your cancerous growth.

Other tests for diagnosing cancer

Blood tests alone are rarely sufficient to diagnose cancer. Additional tests are typically necessary, such as:

• Biopsy: A small tissue sample from an organ or bone marrow is collected and analysed in a lab for cancerous cells.
• Imaging Tests: Techniques like X-rays, CT scans, MRI scans, or PET scans help locate and stage tumours.
• Specialised Tests: Certain cancers require specific diagnostic tests, such as mammograms for breast cancer, Pap smears for cervical cancer, or bone profile blood test for bone cancer.

These additional procedures provide critical information, helping healthcare providers confirm a diagnosis, determine the type and stage of cancer, and guide treatment planning. Together, these methods create a comprehensive approach to cancer diagnosis and management.

Does blood work show early cancer?

Most cancers do not show up in routine blood work, but specialised blood tests may detect early stage cancers in some cases:

• The Galleri Test: This blood test can detect over 50 types of cancer by analysing DNA patterns. It uses DNA sequencing to identify unique markers that indicate cancer and pinpoint its origin.
• Proteomics-based Plasma Test: Proteomics, the study of cell proteins, forms the basis of this test. This additional research besides normal blood testing is yet to validate its effectiveness for widespread use.

Interpreting results from these tests requires being cautious, as false positives or other uncertainties may arise. Always discuss next steps with your healthcare provider for testing or treatment.

Early stage cancers are extremely challenging to diagnose, but routine cancer screenings remain a vital tool. These screenings, tailored to specific types of cancer, can detect abnormalities before symptoms develop. Talk to your provider about appropriate screenings to maintain your health and address potential issues early.

Advancements in blood tests like Galleri and proteomics offer hope for improved early detection, complementing routine screenings and traditional diagnostic tools.

What is the function of cancer blood test?

Blood work, combined with other tests, provides valuable insights for your provider, including:

• Abnormal chemicals or proteins indicating cancer
• High or low blood cell levels linked to cancer
• Cancer staging details
• Treatment effectiveness
• Signs of cancer recurrence

These results guide diagnosis, monitoring, and treatment planning.

How to prepare for cancer blood test?

Your healthcare provider will provide instructions to prepare you for the blood test, which may vary as per the test type. Some tests require fasting for 8 to 12 hours, meaning no food or drinks except water. You might also need to temporarily avoid certain medications. Always follow your provider’s guidelines to ensure accurate results.

What to expect from your cancer blood test?

Collecting a blood sample is a quick process, usually taking just a few minutes. Your healthcare provider will:

• Wrap a tourniquet around your upper arm to make the veins more visible.
• Clean a specific area of your skin, often inside your elbow or on your hand.
• Insert a needle into the cleaned area, which may cause brief stinging or pinching.
• Attach a tube to the needle to collect your blood.
• Remove the tourniquet and the needle once the blood sample is collected.
• Apply pressure to the puncture site to stop bleeding.
• Place a bandage over the site for protection.

After your blood test, you should leave the bandage on for a few hours to protect the site. Your provider may recommend avoiding strenuous activities or exercise for a few hours, as raising your heart rate could increase bleeding.

Most people experience only mild discomfort or bruising at the puncture site, which typically resolves quickly. If you notice prolonged bleeding or other unusual symptoms, contact your healthcare provider.

Risks and side effects of cancer blood test

Blood tests are safe with minimal risk. You might develop a small bruise at the needle site, and rarely, the vein may swell. Applying a warm compress, like a washcloth or heating pad, can help alleviate swelling and discomfort.

Results and follow-up appointments

You will typically receive your blood test results within a day or two, although it may take several days depending on the specific test. Your healthcare provider will inform you of when to expect the results and will discuss them with you during a follow-up appointment.

What if my results are abnormal?

If your blood test shows potential signs of cancer, your healthcare provider will refer you to an oncologist, a specialist in cancer care. The oncologist may conduct additional tests to confirm the diagnosis and determine the appropriate treatment plan.

Cancer treatment generally involves a multidisciplinary approach, where your oncologist will collaborate with various specialists to ensure comprehensive care. These professionals work together to provide the best treatment options, tailored to your diagnosis and individual needs.

Can lipid panel detect cancer?

Healthcare providers do not use lipid panels to detect cancer. A lipid panel measures cholesterol and triglycerides in your blood, helping assess your risk for cardiovascular conditions like heart attack and stroke, not cancer.

Can I still have cancer with normal blood test results?

Yes, you can have cancer even with normal blood test results, as blood work does not detect most types of cancer. However, it can identify certain blood cancers, such as leukaemia, lymphoma, and multiple myeloma, which are exceptions to this limitation.

Summary

In conclusion, while blood tests are valuable tools in diagnosing and managing cancer, they are rarely sufficient on their own for a definitive diagnosis. They can help detect certain blood cancers, monitor treatment effectiveness, and provide insights into cancer staging and recurrence. However, additional tests such as biopsies, imaging, and specialised screenings are often necessary to confirm a diagnosis. For instance, PSA can detect prostate cancer, bone profile blood test can detect bone cancer, or Pap smears can detect cervical cancer. Ultimately, cancer diagnosis and treatment rely on a comprehensive approach involving various tests and expert consultations to ensure accurate results and effective care.

Waiting for cancer test results can make you feel stuck in time, making it difficult to focus on daily activities when the future feels uncertain. Your healthcare provider will conduct several tests to confirm a diagnosis, with blood tests being just one method. They will explain what each test is for and help you understand the meaning of your results.