There are several tests to diagnose cancer. At times, the test results may be suggestive, while at other times, the results are almost conclusive.

As research advances, new tools are developed to help in the early diagnosis of cancer to enable prompt treatment and a better prognosis.

Besides diagnosing the presence of cancer, the diagnostic tests also help in determining the type of cancer and its stage and whether cancer has spread locally or to distant parts of the body (metastasis).

The oncologist only orders the diagnostic tests after the patient has exhibited signs and symptoms suggestive of cancer. Only after there is confirmed clarity on the diagnosis, does the oncologist start treatment.

The most commonly used diagnostic methods include:

Blood tests

The fact is that there is no single reliable blood test to accurately diagnose cancer. In general, they are considered non-conclusive.

Blood testing starts with a complete blood count, which gives an idea about the counts of different blood cells. These include the red blood cells, the white blood cells, and the platelets.

A very high WBC count can indicate blood cancer ( leukemia). A significant drop in blood cell counts can indicate bone marrow depression.

Blood tests detect cancer by identifying tumor markers in the blood. Tumor markers are substances that are found to increase in blood in people with cancer.

The Alfafetoprotein test (AFP) is a tumor marker test in which high AFP levels are indicative of cancers of the liver, testicles, and ovaries.

Similarly, elevated PSA levels are highly suggestive of prostate cancer, but high PSA levels can also be due to non-malignant conditions like BPH or prostatitis.

Read the full not on blood tests to diagnose cancer

Urine cytology

Microscopic examination of urine may reveal cancer cells in malignancies of the urinary tract such as cancer of the kidneys, ureter, and bladder.

Your doctor might recommend a urine cytology test if you have hematuria (blood in your urine).

Urine cytology is usually more useful to diagnose more aggressive cancers than slow-growing cancers.

Diagnostic imaging

Imaging produces pictures of the internal parts of the body and its organs. A trained technician takes the pictures, which are then interpreted by the radiologist. The findings help the oncologist in formulating a treatment plan.

Imaging techniques have undergone improvements and their results have become an important part of early cancer detection of bones and organs such as the stomach and kidneys.

Imaging studies include X-rays, CT Scans, MRIs, Pet scans, Ultrasounds, Mammograms, and more.

Read the full not on imaging studies to diagnose cancer.

Biopsy to diagnose and confirm cancer

Biopsy by far forms the most important and conclusive test of all tests to diagnose cancer. It gives cellular details of the tissue of the lesion or tumor and the histopathologist is able to directly visualize the cancer cells under the microscope. The cancer cells and the normal cells look different under the microscope.

In the case of needle biopsy, only a local anesthetic is used and it can be performed on an outpatient basis. A small tissue sample is removed either by a needle or surgically from the suspicious tumor. It is then examined under a microscope for the presence of cancer cells.

At times, surgical excision of the tumor is advised and slides are prepared from selected parts of the tumor to look for cancer cells. An excision biopsy may require you to be admitted to the hospital.

A biopsy is the only way to confirm the diagnosis of cancer. Read the full note on the biopsy test.


The doctor inserts a flexible fiberoptic endoscope (a long, thin tube that has a telescope and light at its end for viewing) through a body orifice (i.e., rectum) or through a small incision (i.e., arthroscopy).

He views the suspicious tissue or organ through the endoscope, which also helps him to obtain a small piece of the suspicious tissue for histopathology study.

Endoscopy can help to get pieces of the tissues from various parts of the body for the purpose of pathological examination such as:

  • alimentary tract endoscopy  used to study the gastrointestinal tract
  • cystoscopy for the urinary bladder
  • laparoscopy for the abdominal cavity
  • arthroscopy to study joint cavity
  • mediastinoscopy to study lymph nodes in the area between the lungs
  • laryngoscopy to examine tissue in the trachea
  • bronchoscopy to study the bronchial system

Genetic testing for cancer

Genetic testing for cancer is done to estimate your chance of developing cancer. This test searches for specific changes in your genes and chromosomes. These changes are called mutations.

Though it is not used to diagnose or confirm a suspected cancer case, it does approximately evaluate your risk of developing hereditary cancer.

Genetic tests are available for various types of cancers such as cancer of the breast, ovaries, colon, prostate, pancreas, and more. Read the full note on genetic tests to assess cancer risk

Though we’ve been rather complete with this topic along with the links expressed, cancer.net gives in detail the various tests used to diagnose each type of cancer in relation to its location in the body.