|
Complete blood count (CBC): A drop of blood
contains a number of different cell types, including red blood cells
(erythrocytes), macrophages, neutrophils, basophils, eoisinophils, B
lymphocytes, and T lymphocytes, among others. Differences in the number or
appearance of any of these cell populations might serve as an indication
of some underlying illness. The list of possibilities is far too long to
delineate here. Alanine aminotransferase (ALT): The activity of this enzyme is measured in blood plasma. Elevated levels of this enzyme can be an indication of viral hepatitis and other forms of liver disease. Total protein: Measurement of the total
protein concentration in plasma. Elevated concentrations reflect
dehydration, which might be attributable to vomiting, diarrhea, Addison's
disease, diabetic acidosis, and other conditions. Globulin: Globulins are a diverse group of
proteins in the blood, and together represent the second most common
proteins (after albumin) in the bloodstream. An elevation in the level of
serum globulin can indicate the presence of cirrhosis of the liver. Calcium: Increased levels of plasma calcium may indicate the presence of malignant disease or hyperparathyroidism. Less commonly, it could reflect thyrotoxicosis, vitamin D intoxication, the use of thiazide diuretics, sarcoidosis, and other disorders. Reduced levels of calcium may reflect vitamin D deficiency, renal disease, hypoparathyroidism, magnesium deficiency and other disorders. Phosphorus: Increased levels of plasma phosphate ion may indicate imminent renal failure, hypoparathyroidism, acromegaly, excessive phosphate intake, and vitamin D intoxication. Sharply decreased levels of plasma phosphate may reflect vitamin D deficiency, primary hyperparathyroidism, magnesium deficiency, and diabetic ketoacidosis. Glucose: Elevated blood glucose levels may
be an indication of diabetes mellitus. Lower-than-normal blood glucose
levels (hypoglycemia) can be caused in a variety of ways, often
transiently, and must be examined under specific clinical conditions
before relating this finding to any clinical disorders. Electrolytes: This test measures the levels
of charged ions dissolved in the blood and urine, including sodium,
potassium, calcium, magnesium, chloride, bicarbonate, phosphate, sulfate,
and lactate. Virtually all the metabolic processes in the body are
dependent on the presence of these charged ions, the concentrations of
which are tightly controlled. Deviations from normal levels of each of
these cautions can reflect a wide variety of clinical problems, too
numerous to detail here.
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
A laboratory test is a medical procedure that involves testing a sample of
blood, urine, or other tissues or substances in the body. Such tests have
a variety of uses. They are often used as part of a routine checkup to
identify possible changes in a person's health before any symptoms occur.
Laboratory tests also play an important role in diagnosis when a person
has symptoms. In addition, tests may be used to help plan a patient's
treatment, evaluate the response to treatment, or monitor the course of
the disease over time.
Some
laboratory tests are precise, reliable indicators of specific health
problems, while others provide more general information that simply gives
doctors clues to possible health problems. Information obtained from
laboratory tests may help doctors decide whether other tests or procedures
are needed to make a diagnosis or to develop or revise a previously
diagnosed patient's treatment plan. All laboratory test results must be
interpreted in the context of the overall health of the patient and are
generally used along with other exams or tests. The doctor who is familiar
with the patient's medical history and current condition is in the best
position to interpret that person's test results and explain their
implications. Patients are encouraged to discuss questions or concerns
about laboratory test results with the doctor.
