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Medical Tests

Antibody Screening Test
Blood Culture
Bone Scan
Cardiac Blood Pool Imaging
Complement Assays
Contraction Stress Test
Crossmatching
Direct Antiglobulin Test
Hepatitis B Surface Antigen
Herpes Simplex Antibodies
Human Chorionic Gonadotropin
Liver Spleen Scanning
Pelvic Ultrasonography
Percutaneous Renal Biopsy
Percutaneous Transhepatic Cholangiography
Pregnanetriol
Raji Cell Assay
Renal Ultrasonography
Respiratory Syncytial Virus Antibodies
Skin Biopsy
T-And B-Lymphocyte Assays
Ultrasonography of the Spleen
Wound Culture


Medical Tests | Lab Tests

Learn to understand Medical Tests

With the many health problems prevalent today like diabetes, joint pains and heart disease there is an increasing need of taking regular medical tests. It is usually blood tests that have to be taken where you get results which are expressed in numbers that signify the exact quantity of the entity that was measured.

These measured quantities come with a ‘normal range’ in laboratory reports. This normal range numbers consists of a lower number and higher number, and are the amounts the laboratory thinks the value should show to indicate a healthy body. So when you have a medical test, sometimes your measurement has to lie within this range, and at times, outside this range.

Whether the value has to lie within or outside the range depends on the particulars. First thing that has to be taken into consideration is what is being measured, and why it is being measured. Usually doctors prescribe medical tests to get answers to questions regarding a specific health condition. This is because sometimes different diseases have similar symptoms which make it difficult to decide what disease the patient is suffering from.

Sometimes the doctor will need to have a blood test done to find out if the patient is suffering from the production of too little thyroid hormones that leads to obesity. With a medical test measuring the amount of thyroid hormone in the blood stream, the doctor will be able to find out if the obesity in the patient is due to hormones or a bad lifestyle.

There are some blood tests that give results in only a single direction; like the blood urea nitrogen test that assesses kidney function. If the reading here is high, it indicates that the kidney is impaired and if the reading is low, it means nothing at all. Despite there being no lower limits for this test, there still is the lower range mentioned in the ‘normal range’ of blood tests.

So now one wonders how normal ranges are created in the first place. They are basically created by statistics that are generated by collecting measurements from healthy volunteers. In the case of BUN measurement, the readings for this test is obtained from 100 healthy individuals and then added to be divided by 100 to get the average and normal range for BUN test.

If the upper and lower numbers are required, tests are done on 100 healthy people, and then these measurements are plugged into a mathematical formula to reach a standard deviation which shows how widely the numbers are spread apart. Then the numbers that are farthest apart produce a large standard deviation while the numbers close together produce a smaller standard deviation.

With this, you have to find out how many standard deviations that lie above and below average should and can be considered normal. Blood tests usually choose two standard deviations on either side to determine the normal range. The doctor is the best person to decide where your blood test results falls in a blood test.


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