How to understand the blood test

To understand the blood test it is necessary to pay attention to the type of test the doctor ordered, the reference values, the laboratory where the test was performed and the result obtained, which must be interpreted by the doctor.

After the blood count, the most requested blood tests are VHS, CPK, TSH, PCR, liver and PSA tests, the latter being an excellent marker of prostate cancer. See which blood tests detect cancer.

ESR – erythrocyte sedimentation rate

The VSH test is requested to investigate inflammatory or infectious processes, and is usually requested together with the blood count and the C-reactive protein (CRP) dosage. This examination consists of observing the amount of red blood cells that sediment in 1 hour. In men under 50, the normal VSH is up to 15 mm / h and up to 30 mm / h for men over 50. For women under 50, the normal VSH value is up to 20 mm / h and up to 42 mm / h for women over 50. Understand what the VHS exam is and what it can indicate.

It assesses the occurrence of infectious and inflammatory processes, in addition to being asked to monitor the evolution of diseases and response to therapy.High : Cold, tonsillitis, urinary tract infection, rheumatoid arthritis, lupus, inflammation, cancer and aging.Low : Polycythemia vera, sickle cell anemia, congestive heart failure and in the presence of ulcers.

CPK – Creatinofosfoquinase

The CPK blood test is requested in order to check for the occurrence of diseases involving the muscles and the brain, being mainly requested to assess cardiac function, being requested together with myoglobin and troponin. The reference value of CPK in men is between 32 and 294 U / L and in women between 33 and 211 U / L . Learn more about the CPK exam.

Evaluates cardiac, brain and muscle functionHigh : infarction, stroke, hypothyroidism, shock or electrical burn, chronic alcoholism, pulmonary edema, embolism, muscular dystrophy, strenuous exercise, polymyositis, dermatomyositis, and after intramuscular injections recent seizures of cocaine use.

TSH, T3 total and T4 total

The measurement of TSH, T3 and total T4 are requested in order to assess the functioning of the thyroid. The reference value of the TSH test is between 0.3 and 4µUI / mL, which may vary between laboratories. Learn more for what the TSH exam is for.

TSH – Thyroid stimulating hormoneHigh : Primary untreated hypothyroidism due to the removal of part of the thyroid.Low : Hyperthyroidism
T3 – Triiodotironina totalHigh : In treatment with T3 or T4.Low : Severe diseases in general, postoperative, in the elderly, fasting, use of medications such as propranolol, amiodarone, corticosteroids.
T4 – Total thyroxineHigh : Myasthenia gravis, pregnancy, pre-eclampsia, severe illness, hyperthyroidism, anorexia nervosa, use of medications such as amiodarone and propranolol.Low : Hypothyroidism, nephrosis, cirrhosis, Simmonds’ disease, pre-eclampsia or chronic renal failure.

PCR – C-reactive protein

C-reactive protein is a protein produced by the liver whose dosage is requested when inflammation or infection in the body is suspected, being elevated in the blood under these conditions. The normal CRP value in the blood is up to 3 mg / L , and may vary between laboratories. See how to understand the PCR exam.

Indicates whether there is inflammation, infection or cardiovascular risk.High : Arterial inflammation, bacterial infections such as appendicitis, otitis media, pyelonephritis, pelvic inflammatory disease; cancer, Crohn’s disease, heart attack, pancreatitis, rheumatic fever, rheumatoid arthritis, obesity.

TGO and TGP 

TGO and TGP are enzymes produced by the liver and whose concentration in the blood is increased when there are lesions in this organ, being considered excellent indicators of hepatitis, cirrhosis and liver cancer, for example. The normal value of TGP varies between 7 and 56 U / L and that of TGO between 5 and 40 U / L. Learn how to understand the TGP exam and the TGO exam.

TGO or ASTHigh : Cell death, infarction, acute cirrhosis, hepatitis, pancreatitis, kidney disease, cancer, alcoholism, burns, trauma, crush injury, muscular dystrophy, gangrene.Low : Uncontrolled diabetes, beriberi.
TGP or ALTHigh : Hepatitis, jaundice, cirrhosis, liver cancer.

PSA – Benign Prostatic Antigen

PSA is a hormone produced by the prostate, and is normally requested by the doctor to evaluate the functioning of this gland. The PSA reference value is between 0 and 4 ng / mL , however it can vary according to the age of the man and the laboratory in which the test was performed, with the increased values ​​usually indicative of prostate cancer. Learn how to understand the PSA exam result.

Evaluates prostate functionUpper : Enlarged prostate, prostatitis, acute urine retention, prostate needle biopsy, trans-urethral resection of the prostate, prostate cancer.

Other exams

Other tests that can be ordered to assess a person’s general health are:

  • CBC : used to evaluate white and red blood cells, being useful in the diagnosis of anemia and leukemia, for example – Learn how to interpret the CBC ;
  • Cholesterol : asked to assess HDL, LDL and VLDL, relating to the risk of cardiovascular disease;
  • Urea and creatinine : serves to assess the degree of kidney impairment and can be done from the dosage of these substances in the blood or urine – Understand how the urine test is done ;
  • Glucose : asked to diagnose diabetes. As well as cholesterol-related tests, to check blood glucose levels, the person must be fasting for at least 8 hours – Learn more about fasting to perform the blood test ;
  • Uric acid : serves to assess the functioning of the kidneys, but must be associated with other tests, such as the measurement of urea and creatinine, for example;
  • Albumin : it serves to help in the assessment of the individual’s nutritional status and to check the occurrence of heart and kidney diseases, for example.

The pregnancy blood test is Beta hCG, which can confirm pregnancy even before menstruation is late. See  how to understand the results of the beta-hCG exam.

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