Understanding Laboratory Tests

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What are Laboratory Tests?

Doctors use laboratory tests to diagnose cancer, assess its severity, and monitor treatment progress and side effects. A laboratory test is a procedure in which a sample of a bodily fluid (i.e. blood, urine, mucus) or tissue (i.e. tumor sample, lymph node, bone marrow) is examined under a microscope in a laboratory. Laboratory tests can provide important information about a patient’s general health and organ function, and may be used for any of the following reasons depending on the type of cancer:

Laboratory tests
  • To detect signs and symptoms of cancer
  • To monitor side-effects and complications of treatment
  • To rule out other diseases that may be causing symptoms
  • To monitor the effectiveness of treatment
  • To monitor for a cancer recurrence
  • To help diagnose a disease
  • To help stage a disease, plan treatment, and determine the prognosis
Blood Tests

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Blood Tests

Routine blood tests are a common part of cancer screening, diagnosis, staging, and treatment. Blood tests are used to detect the levels of different substances in the blood, and may be recommended to monitor general health and organ function during cancer treatment.

Collapsed Complete Blood Count (CBC)

Collapsed Blood Chemistry Profile

Collapsed Hormone Panel
Urine Tests

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Urine Tests

Urine tests are used to measure the levels of different substances in the urine. These tests can also be useful in monitoring general health and organ function, and ruling out signs of infection.

Collapsed Urinalyis

Collapsed 24-hour Urine Analysis

Collapsed Urine Culture

Collapsed Urine Cytology
Stool Tests

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Stool Tests

For some cancers, the doctor may recommend testing the levels of different substances in the stool or checking for blood in the stool.

Collapsed Fecal Occult Blood Test (FOBT)

Collapsed Fecal Immunochemical Test (FIT)

Collapsed Stool DNA Test
Tumor Markers

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Tumor Markers

Tumor markers are substances that can be found in higher than normal amounts in a person's blood, urine, or bodily tissues when they have a specific type of cancer. Some substances are tumor markers for a specific cancer, while others are tumor markers for multiple cancers. Tumor markers can be used in different ways, depending on the specific type of cancer. Most tumor markers can be used to monitor the extent of the disease and the patient’s response to treatment. Some tumor markers can also be used to detect a cancer recurrence, to give doctors an idea of the prognosis (chance of recovery), to help doctors with treatment-planning, to confirm a diagnosis (in conjunction with other tests), and/or to screen for cancer in undiagnosed individuals.

Tumor markers are not perfect. Not all cancers produce tumor markers. High levels of a tumor marker do not necessarily mean you have cancer, and low levels do not necessarily mean you do not. Elevated levels of tumor markers may be caused by other types of cancer and non-cancerous diseases. In some cancers, tumor markers are not detectable until an advanced stage. Additionally, tumor markers behave differently in different patients. Two patients with the same levels of tumor markers in the blood could be at very different stages of the disease.

Collapsed Common Tumor Markers

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Biopsy

A biopsy is the only way to be certain if cancer is present. During a biopsy, the doctor removes a tissue sample from a suspicious area and sends it to a laboratory to be examined under a microscope. This tissue sample may be taken from the tumor or from other bodily tissues such as the lymph nodes, bone marrow, mucus coughed up from the lungs (sputum cytology), urine (urine cytology), blood (peripheral blood smear), or fluid from the abdomen (peritoneal washings). The sample may be extracted using a variety of methods, depending on the type and location of the cancer. For many cancers, the doctor can extract a cell sample using a needle inserted through the skin. For cancers located more deeply in the body, the doctor may use an endoscope (a flexible, narrow tube with a camera and light on the end) or laparoscope to reach the tumor and perform a biopsy. For other cancers, such as skin cancer or sarcoma, the doctor may use a special surgical instrument or scalpel to remove a tissue sample.

Genetic Testing

Genetic Testing

Genetic testing looks for mutations or alterations in a person’s genes. Studies have shown that genetic variations in the chromosomes can predispose certain people to cancer. For example, women with Hereditary Breast and Ovarian Cancer Syndrome (HBOC) have mutations in the BRCA1 or BRCA2 genes that greatly increase the risk of developing breast or ovarian cancer. People with Lynch Syndrome, also know as Hereditary non-polyposis colon cancer (HNPCC), have genetic mutations that increase their risk of developing colorectal cancer. There are over fifty hereditary syndromes that can increase the risk of developing cancer, including: Familial Adenomatous Polyposis, Li-Fraumeni Syndrome, Multiple Endocrine Neoplasia, Neurofibromatosis, Birt-Hogg-Dubé syndrome, Peutz-Jeghers Syndrome, and others. Genetic testing allows people to determine if they have any genetic abnormalities that may increase their risk for certain cancers. Genetic counseling helps patients understand how genetic changes are passed from one generation to the next, and the risk of passing the mutation to their children. Genetic counseling also helps patients understand possible risk-reduction strategies such as pre-emptive mastectomy and salpingo-oopherectomy, so they are better prepared to make decisions.

Genomic Testing

Genomic Testing

Genomic testing refers to new tests that are available to obtain information about the molecular characteristics of a tumor. Cancer is a disease caused by certain changes in the genes that control how our cells grow and function. Genes are made up of DNA and carry instructions for making RNA, and then RNA to proteins that control how our cells behave. Changes, such as mutations in the genes or an alteration in the number of genes (amplification etc.), can cause cells to make too many proteins or cause proteins to not function properly. These proteins can cause normal cells to grow out of control and become cancerous.

Genomic testing can identify specific genetic changes in the DNA or RNA expression level of cells that cause cancer cells to grow and multiply. By identifying the genetic changes in the DNA or RNA of your cancer cells, doctors can recommend new targeted therapies that attack the specific genetic changes causing your cancer to grow.

Cellular Tests

Cellular Tests

The following tests may be performed to confirm a cancer diagnosis and identify specific characteristics of the cancer cells. This information may help the doctor determine the sub-type of the disease, the status of different receptors, the prognosis, and potentially effective treatments.

Collapsed Immunohistochemical Staining

Collapsed Flow Cytometry (Fluorescence-activated cell sorting, FACS)

Collapsed Cytogenetics

Collapsed Fluorescent in situ hybridization (FISH)

Collapsed Polymerase Chain Reaction (PCR)
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