PSAThis test measures the amount of prostate specific antigen (PSA) in the blood. It was developed as a tumour marker to screen for and to monitor prostate cancer. It is a good tool, but not a perfect one. Elevated levels of PSA are associated with prostate cancer, but they may also be seen with prostatitis (inflammation of the prostate) and benign prostatic hyperplasia (BPH). Mild to moderately increased concentrations of PSA may be seen in those of African American heritage, and levels tend to increase in all men as they age.
PSA is a protein produced primarily by cells in the prostate, a small gland that encircles the urethra in males and produces a fluid that makes up part of semen. Most of the PSA that the prostate produces is released into this fluid, but small amounts of it are also released into the bloodstream.
PSA is NOT diagnostic of cancer. The gold standard for identifying prostate cancer is still the prostate biopsy, collecting small samples of prostate tissue and identifying abnormal cells under the microscope. The goal of testing is to minimize unnecessary biopsies and to detect clinically significant prostate cancer while it is still confined to the prostate. The term clinically significant is important because while prostate cancer becomes relatively common in men as they age, many of the cases are very slow-growing. Doctors must try to both detect prostate cancer and to differentiate between slow-growing cases and prostate cancers that may grow aggressively and metastasize (spread to other parts of the body).
Complete Blood CountThe Complete Blood Count (CBC) test is an automated count of the cells in the blood. A standard CBC includes the following:
- number of white blood cells (WBC)
- number of red blood cells (RBC)
- hemoglobin content (Hgb)
- hematocrit (Hct)
- mean corpuscular volume (MCV)
- mean corpuscular hemoglobin (MCH)
- mean corpuscular hemoglobin concentration (MCHC)
- platelet count and volume.
Blood consists of cells suspended in a liquid called plasma. These cells - the RBCs, WBCs, and platelets - are produced and mature primarily in the bone marrow. Under normal circumstances, they are released into the bloodstream as needed.
White Blood Cells (WBCs)There are five different types of WBCs that the body uses to maintain a healthy state and to fight infections or other causes of injury. They are neutrophils, lymphocytes, basophils, eosinophils, and monocytes. They are present in the blood at relatively stable percentages. These numbers may temporarily shift higher or lower depending on what is going on in the body. For instance, an infection can stimulate a higher concentration of neutrophils (a "shift to the left") to fight off bacterial infection. With allergies, there may be an increased number of eosinophils that release certain chemicals (anti-histamines) that minimize the allergic effect. Lymphocytes may be stimulated to produce immunoglobulins (antibodies). And in certain disease states, such as leukaemia, abnormal and immature white cells (blasts) rapidly multiply, increasing the WBC count.
Red Blood Cells (RBCs)RBCs are pale red in color and shaped like a donut with a thinner section in the middle instead of a hole. They have hemoglobin inside them, a protein that transports oxygen throughout the body. The CBC determines whether there are sufficient RBCs present and whether the population of RBCs appears to be normal. RBCs are normally all the same size and shape; however, variations can occur with vitamin B12 and folate deficiencies, iron deficiency, and with a variety of other conditions. If there are insufficient normal RBCs present, the patient is said to have anaemia and may have symptoms such as fatigue and weakness. Much less frequently, there may be too many RBCs in the blood. In extreme cases, this can interfere with the flow of blood through the veins and arteries.
PlateletsPlatelets are special cell fragments that play an important role in blood clotting. If a patient does not have enough platelets, he will be at an increased risk of excessive bleeding and bruising. The CBC measures the number and size of platelets present. With some conditions and in some people, there may be giant platelets or platelet clumps that are difficult for the haematology instrument to accurately measure.
CholesterolCholesterol is a substance (a steroid) that is essential for life. It forms the membranes for cells in all organs and tissues in your body. It is used to make hormones that are essential for development, growth and reproduction. It forms bile acids that are needed to absorb nutrients from food. A small amount of your body's cholesterol circulates in the blood in complex particles called lipoproteins. These lipoproteins include some particles that carry excess cholesterol away for disposal (see HDL, good cholesterol) and some particles that deposit cholesterol in tissues and organs (see LDL, bad cholesterol). The test for cholesterol measures all cholesterol (good and bad) that is carried in the blood by lipoproteins.
Comprehensive Metabolic PanelThe Comprehensive Metabolic Panel (CMP) is a frequently-ordered panel that gives your doctor important information about the current status of your kidneys, liver, and electrolyte and acid/base balance as well as of your blood sugar and blood proteins. Abnormal results, and especially combinations of abnormal results, can indicate a problem that needs to be addressed.
The CMP is used as a broad screening tool to evaluate organ function and check for conditions such as diabetes, liver disease, and kidney disease. The CMP may also be ordered to monitor known conditions, such as hypertension, and to monitor patients taking specific medications for any kidney- or liver-related side effects.
While the individual tests are sensitive, they do not usually tell your doctor specifically what is wrong. Abnormal test results or groups of test results are usually followed-up with other specific tests to confirm or rule out a suspected diagnosis.
The CMP includes:
- Total Protein
- CO2 (carbon dioxide, bicarbonate)
- BUN (blood urea nitrogen)
- ALP (alkaline phosphatase)
- ALT (alanine amino transferase, also called SGPT)
- AST (aspartate amino transferase, also called SGOT)
UrinalysisA urinalysis is a group of tests that detect and semi-quantitatively measure various compounds that are eliminated in the urine, including the by-products of normal and abnormal metabolism as well as cells, including bacteria, and cellular fragments. Urine is produced by the kidneys, located on either side of the spine at the bottom of the ribcage. The kidneys filter wastes and metabolic by-products out of the blood, help regulate the amount of water in the body, and conserve proteins, electrolytes, and other compounds that the body can reuse. Anything that is not needed is excreted in the urine and travels from the kidneys to the bladder, through the urethra, and out of the body. Urine is generally yellow and relatively clear, but every time someone urinates, the colour, quantity, concentration, and content of the urine will be slightly different because of varying constituents.
Many disorders can be diagnosed in their early stages by detecting abnormalities in the urine. These include increased concentrations of constituents that are not usually found in significant quantities in the urine, such as: glucose, protein, bilirubin, red blood cells, white blood cells, crystals, and bacteria. They may be present because there are elevated concentrations of the substance in the blood and the body is trying to decrease blood levels by "dumping" them in the urine, because kidney disease has made the kidneys less effective at filtering, or in the case of bacteria, due to an infection.
HaemoglobinThis test measures the amount of haemoglobin, a protein found in red blood cells, in a blood sample, which is a good indication of the blood's ability to deliver oxygen to tissues and organs and to transport the waste product carbon dioxide to the lungs, where it is exhaled. If your haemoglobin levels are low, you may have anaemia, a condition in which your body is not getting enough oxygen, causing fatigue and weakness.
The haemoglobin rises when the number of red blood cells increases. The haemoglobin falls to less than normal, indicating anaemia, when your body decreases its production of red blood cells, increases its destruction of red blood cells, or if blood is lost due to bleeding.
CRPC-reactive protein (CRP) is a substance made by the liver and secreted into the bloodstream. Its concentration increases within a few hours after the start of an infection, making it especially valuable for monitoring infections. Its rise in the blood often precedes pain, fever, or other clinical indicators. The level of CRP can jump a thousand-fold in response to inflammation. It drops relatively quickly as soon as the inflammation passes, making it a valuable test to monitor effectiveness of treatment.
Micro-albuminThe microalbumin test is an early indicator of kidney failure. It measures the tiny amounts of albumin that the body begins to release into the urine several years before significant kidney damage becomes apparent. Albumin is a protein that is produced in the liver. It is present in high concentrations in the blood, but when the kidneys are functioning properly, virtually no albumin is allowed to leak through into the urine. If a person's kidneys become damaged or diseased, however, they begin to lose their ability to filter proteins out of the urine. This is frequently seen in chronic diseases, such as diabetes and hypertension, with increasing amounts of protein in the urine reflecting increasing kidney failure.
Since the albumin molecule is small, it is one of the first proteins to be detected in the urine with kidney damage. Patients who have consistently detectible amounts of albumin in their urine (microalbuminuria) have an increased risk of developing progressive kidney failure and cardiovascular disease in the future.
Liver PanelA liver panel, also known as liver (hepatic) function tests or LFT, is used to detect, evaluate, and monitor liver disease or damage. It usually consists of seven tests that are run at the same time on a blood sample. These include:
- Alanine aminotransferase (ALT) - an enzyme mainly found in the liver; the best test for detecting hepatitis
- Alkaline phosphatase (ALP) - an enzyme related to the bile ducts; often increased when they are blocked
- Aspartate aminotransferase (AST) - an enzyme found in the liver and a few other places, particularly the heart and other muscles in the body
- Bilirubin - two different tests of bilirubin often used together (especially if a person has jaundice): total bilirubin measures all the bilirubin in the blood; direct bilirubin measures a form that is conjugated (combined with another compound) in the liver
- Albumin - measures the main protein made by the liver and tells whether or not the liver is making an adequate amount of this protein
- Total Protein - measures albumin and all other proteins in blood, including antibodies made to help fight off infections
INRThe prothrombin time test measures how long it takes for a clot to form in a sample of blood. In the body, the clotting process involves a series of sequential chemical reactions. One of the final steps is the conversion of prothrombin to thrombin. Prothrombin is one of several clotting factors that are produced by the liver. The prothrombin test evaluates the integrated function of these factors and the body's ability to produce a clot in a reasonable amount of time.
The test is usually measured in seconds and is compared to values in healthy individuals. Because the reagents (chemicals) used to perform the PT test vary from one laboratory to another and even within the same laboratory over time, the normal values also will fluctuate. To standardize results, a World Health Organization committee developed and recommended the use of the Internationalized Normalized Ratio (INR) with the test for patients who are receiving anticoagulation therapy (such as warfarin). The INR is a calculation that adjusts for changes in the PT reagents and allows for results from different laboratories to be compared.
HbA1CWhile not used for diagnosing diabetes, the HbA1c test provides an assessment of the degree to which blood glucose has been elevated over an extended time period. It measures the amount of binding glucose has done to haemoglobin of red blood cells over the previous 2-3 months. The higher the concentration of glucose in the blood, the more binding it will do. All red blood cells have some glucose bound to them.
Bone Density ScanningBone density testing is used to assess the strength of the bones and the probability of fracture in persons at risk for osteoporosis. The test, referred to as bone densitometry or bone mineral density scan (BMD), is a simple, non-invasive procedure that takes just minutes.
Unlike a bone scan, bone densitometry testing does not involve the administration of radioactive contrast material into the bloodstream. The most commonly used test is known as a dual energy x-ray absorptiometry (DEXA) scan - we perform this scan on the forearm.