Learn About 5 Common Lab Tests for Cancer Diagnosis

A variety of lab tests may be useful in diagnosing cancer. Blood and urine are the most common samples used in lab tests. Blood tests for cancer will help the doctors to identify the possible health problems. 

Single test will not accurately diagnose cancer. Physicians often suggest other tests such as imaging tests to have a clear idea.

Lab test for cancers can also help in staging the cancer, planning treatment, monitoring the health status during the treatment and check if the cancer has recurred. Here are some common lab tests for cancer useful in diagnosis.

Common lab tests for cancer detection:

1. Complete blood count (CBC), a lab test for cancer:

This is one common lab test for cancer, performed to measure the number of each type of blood cell, namely white blood cells, red blood cells, and platelets in your blood. This test also measures the amount of a protein, haemoglobin, which helps in carrying oxygen to the tissues and percentage of red blood cells in the blood.

Blood cancers can cause too high or too low blood cells. Complete blood count helps in detecting the variation in blood cells. If abnormal CBC values are found, and if any cancer condition is suspected, your physician may recommend bone marrow biopsy.

2. Tumour marker tests: 

Tumour markers are substances found in blood, body fluids or body tissues. They can either be produced by cancer cells or the body in response to cancer cells. It may be used to decide appropriate treatment. Cancer cells with increased levels of tumour markers may respond to treatment with a medicine that targets the marker. It may also be used to find out how well the treatment works and monitor cancer recurrence. 

Some examples of tumour markers:

(a) Prostate-Specific Antigen (PSA) is a substance present in low concentration in men. High concentrations of PSA may indicate prostate cancer, but other prostate diseases such as BPH (Benign prostatic hyperplasia) and prostatitis can also increase the PSA levels. 

(b) Alpha-Fetoprotein (AFP) is usually found in high levels in pregnant women. High concentration of AFP in women who are not pregnant and men may indicate cancers of the liver, testicle or ovary. 

(c) CA 19-9 protein levels generally elevates in benign conditions as well in malignant conditions. The diagnosis is based on the level CA 19-9  in the body. These results are interpreted usually with the results of other lab tests for cancer, such as biopsy and imaging to diagnose cancer.

3. Immunophenotyping (flow cytometry):

Immunophenotyping is usually done on cells collected from blood or bone marrow samples. It may also be performed on other body fluids. It is performed to see if any abnormal blood cells are present. It also detects the number of abnormal cells. 

This lab test for cancer helps in diagnosing some types of blood cancers and helps in specifying the type of blood cancer.

4. Sputum cytology: 

Sputum cytology involves the investigation of sputum under a microscope to see if any abnormal or cancerous cells are present. It helps in the diagnosis of lung cancer. This lab test for cancer is more useful in the diagnosis of squamous cell lung cancers. Further testing will be performed to confirm the diagnosis.
 

5. Urinalysis: 

This lab test for cancer detects the presence of blood or other substances such as protein in the urine sample. Even though blood in the urine is an usual indication of any infection, or other non cancerous problems, it could be the first sign of bladder cancer. It may be helpful in the diagnosis of cancers of the kidney and urinary tract.

Presence of high protein in urine could be a sign of multiple myeloma, a type of blood cancer.

 Myeloma protein is an abnormal antibody present in the urine sample of multiple myeloma patients. 

Physicians detect a type of cancer through advanced diagnostic tests and recommend appropriate treatment and specific cancer medicines. 
 

Frequently asked Questions:

Are there blood tests for cancer detection?

Blood tests for cancer are recommended to look for signs of cancer. They are largely helpful in detecting blood cancers but a blood test alone cannot be used in confirming the diagnosis. They give your doctor an idea of how well your organs are functioning.

What blood tests can detect cancer?

As we discussed in the previous question, tests involving blood samples can be helpful in cancer diagnosis. Examples of blood tests which are helpful in cancer detection are complete blood count (CBC), tumour marker tests, and immunophenotyping. 

Can a CBC detect breast cancer?

A Complete blood count (CBC) test is one of the common blood tests for cancer. It measures the quality of blood cells in the person’s blood sample. It is recommended during breast cancer diagnosis to check your general health. Biopsies and imaging tests will confirm the diagnosis. It may be done before or after breast cancer surgery to make sure your bone marrow is functioning well.

Understanding the results:

A definitive diagnosis of cancer cannot be provided by the lab tests alone. Test results can be affected by foods, medications, etc. To avoid the false results, physicians may repeat the tests, or may recommend other diagnostic tests such as CT scan, biopsies, etc. to confirm the cancer diagnosis.