Blood tests

How to Interpret a Blood Test

Max. D Gray
By Max. D Gray. Updated: March 24, 2022
How to Interpret a Blood Test

Blood tests are one of the diagnostics most commonly used to determine a person's health condition. Sometimes we are given results and do not understand what it means to have a high or low value. So in we explain how to interpret a blood test.

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Steps to follow:


Typically we have blood removed to analyse our biochemistry (green) and Complete Blood Count (CBC) (violet). Next we will see the different parameters resulting from each sample.


In the section of biochemistry we can find:

  • Glucose: Normal Values: 70 mg / dl to 120 mg / dl. For the reading to be valid the analysis should be done on an empty stomach. When values above 120 mg / dl are obtained, your doctor must make more tests to rule out or confirm diabetes.
  • Creatinine: Normal range: 0.4 to 1.2 mg / dl. If you present high levels of creatinine it may be indicative of a renal pathology, however it may be due to processes in muscular persons or dehydration.
  • Bilirubin: Normal Values: 0 to 1.1 mg / dl. High levels are symptoms of obstruction by gallstones or liver damage.
  • Uric acid: Normal range: 3.5 to 7.2 mg / dl. High values of this parameter is usually due to a diet rich in protein (meat, oily fish or seafood)
  • Transaminases: Normal values of GGT: 11-50 U / L; GOT: 0 to 37 U / L; GPT: from 0-41 U / L. They are indicators of liver problems when they have high values, this is common in alcoholics, which the GGT is elevated.
  • Iron: Normal values: from 70 to 140 mg / l. Iron decreased values usually indicate anaemia.
  • Ferritin: Normal values: from 15 to 150 ng / ml in women, and 15 to 300 ng / ml in men. Higher values may be due to liver disease or frequent red blood cell transfusions. Low values may indicate: iron deficiency anemia, heavy menstrual bleeding or poor absorption of iron by intestinal pathology.

About Complete Blood Count (CBC):

  • Red Blood Cells (RBC): Normal Values: Women: 4.2 to 5,600,000 / mm³. Men: 4.8 to 5,600,000 / mm³. Higher values may be due to smoking, respiratory failure or living in places with high altitude above sea level. Low levels may be due to bleeding and anemia.
  • Leukocytes: Normal Values: 4500-10600 / ml. When we presented high values it usually due to infection. Low levels due to taking of antibiotics, renal or metabolic disease or failure in bone marrow.
  • Haemoglobin: Normal Values: Men: 13.8 to 17.2 g / dL. Women: 12.1 to 15.1 g / dL. A high or low haemoglobin count can indicate a disease or condition.
  • Mean Corpuscular Volume (MCV): Normal values: 80-97 fl. It is the size of red blood cells. A high value may be due to low levels of iron. A low level can be a deficit in vitamin B12, folic acid or due to alcoholism.
  • Hematocrit: Normal Values: Men: 40.7 to 50.3%. Women: 36.1 to 44.3%. Also depends on the altitude of the residential area. Low values may be due to anemia or bleeding, and high values due to diarrhoea or large burns.

These results will usually be delivered by your General Practicioner, who will answer any questions that you may have when reviewing your blood test.

This article is merely informative, oneHOWTO does not have the authority to prescribe any medical treatments or create a diagnosis. We invite you to visit your doctor if you have any type of condition or pain.

If you want to read similar articles to How to Interpret a Blood Test, we recommend you visit our Diseases & secondary effects category.


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Judy Collins
My husband is having severe frequent urination problems (74yrs), no burning, but his Neutrolfios% is 35/00 instead of between 55.00-65.00. There is slight elevation in the linfocitos, Monocitos, Eosinofilos, and Basofilos. He just recently got out of the hospital with a bout of E-coli, so I wonder it his body is still battling infection..
Monica LeBowsky
This info is very helpful to me as my Doctors want me to get a liver assessment for a liver transplant! I may have Thalassemia also. My blood work is a challenge to the Doctors! I find your info on food very helpful as that is part of my treatment! I have lost almost 200 # in less than a year due to the fruit, veggie, lean meat, legumes, and whole grain diet (1400 calorie) I am on with many meds. I have lymphedema, NASH, and anemia among other DX. Thanks for your help!
How to Interpret a Blood Test