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My doctor ordered some blood tests for me. I would like to understand what each test is for, meaning what information could be gathered from the results.
I have read that some of these, such as CRP, are no longer relevant or often used. Is that true?
C-reactive protein (CRP) is produced by the liver. The level of CRP rises when there is inflammation throughout the body. It is one of a group of proteins called "acute phase reactants" that go up in response to inflammation.
So, when there is an inflammation anywhere in your body, the amount of C-reactive protein in your blood will rise.
The CRP test is a general test to check for inflammation in the body. It is not a specific test. That means it can reveal that you have inflammation somewhere in your body, but it cannot pinpoint the exact location.
Source: Medlineplus.gov
Test Results
For Inflammation:
A test result showing a CRP level greater than 10 mg/L is a sign of serious infection, trauma or chronic disease, which likely will require further testing to determine the cause.
For Heart Diseases
If you're having an hs-CRP test to evaluate your risk of heart disease, there is a high risk if you have an hs-CRP level greater than 2.0 mg/L.
Source: MayoClinic.org
ESR stands for erythrocyte sedimentation rate. It is commonly called a "sed rate." [...] This test can be used to monitor inflammatory diseases or cancer. It is not used to diagnose a specific disorder. (Emphasis mine)
Basically, they measure how long red blood cells (erythrocytes) take to travel down a thin tube.
Source: Medlineplus.gov
Test Results
Results from your sed rate test will be reported in the distance in millimeters (mm) that red blood cells have descended in one hour (hr). The normal range is 0-22 mm/hr for men and 0-29 mm/hr for women. The upper threshold for a normal sed rate value may vary somewhat from one medical practice to another.
Source: MayoClinic
An alpha-fetoprotein (AFP) blood test checks the level of AFP in a pregnant woman's blood. AFP is a substance made in the liver of an unborn baby (fetus).
This is a very solid indication whether one is pregnant or not. It can also help to asses the health of the fetus.
If one is not pregnant, it is highly probable that there are problems with the liver if a high amount of AFP can be found in the blood.
Source: WebMD
Test Results
For women who aren’t pregnant as well as men, the normal amount of AFP is usually less than 10 nanograms per milliliter of blood. If your AFP level is unusually high but you aren’t pregnant, it may indicate the presence of certain cancers or liver diseases.
Source: Healthline.com
The carcinoembryonic antigen (CEA) test measures the amount of this protein that may appear in the blood of some people who have certain kinds of cancers, especially cancer of the large intestine (colon and rectal cancer). It may also be present in people with cancer of the pancreas, breast, ovary, or lung.
This protein is usually only produced in the fetus, so a high level of CEA in the blood can be linked to cancer.
Source: WebMD
Test Results
The normal range is 0 to 2.5 micrograms per liter (mcg/L). In smokers, the normal range is 0 to 5 mcg/L.
Source: Medlineplus.gov
The White Blood Cell Count (WBC) determines the amount of leukocytes, or white blood cells in your blood.
The leukocytes play a vital role in your immune system. Generalized:
These cells help fight infections by attacking bacteria, viruses, and germs that invade the body.
Having a higher or lower number of WBCs than normal may be an indication of an underlying condition. A WBC count can detect hidden infections within your body and alert doctors to undiagnosed medical conditions, such as autoimmune diseases, immune deficiencies, and blood disorders.
This is a standard part of any blood test.
Source: healthline.com
Test Results
The normal number of WBCs in the blood is 4,500 to 11,000 white blood cells per microliter (mcL) or 4.5 to 11.0 x 10^9/L.
Normal value ranges may vary slightly among different labs. Some labs use different measurements or may test different specimens. Talk to your doctor about your test results.
Source: Medlineplus.gov
An RBC count is a blood test that measures how many red blood cells (RBCs) you have.
RBCs contain hemoglobin, which carries oxygen. How much oxygen your body tissues get depends on how many RBCs you have and how well they work.
This is a standard part of any blood test.
Source: Medlineplus.gov
Test Results
A normal range in adults is generally considered to be 700,000 to 5.2 million red blood cells per microliter (mcL) of blood for men and 500,000 to 4.6 million red blood cells per mcL of blood for women. In children, the threshold for high red blood cell count varies with age and sex.
Source: MayoClinic
Platelets are parts of the blood that help the blood clot. They are smaller than red or white blood cells.
The number of platelets in your blood can be affected by many diseases. Platelets may be counted to monitor or diagnose diseases, or to look for the cause of too much bleeding or clotting.
This is a standard part of any blood test.
Source: Medlineplus.org
Test Results
A normal platelet count is between 150,000 and 450,000 platelets per microliter (one-millionth of a liter, abbreviated mcL). The average platelet count is 237,000 per mcL in men and 266,000 per mcL in women.
A platelet count below 150,000 per mcL is called thrombocytopenia, while a platelet count over 450,000 is called thrombocytosis. Platelets seem to have a large backup capacity: blood typically still clots normally as long as the platelet count is above 50,000 per mcL (assuming no other problems are present). Spontaneous bleeding doesn’t usually occur unless the platelet count falls to 10,000 or 20,000 per mcL.
Source: WebMD Answers
