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Understanding Lab Values


Recently I have had inquires about what do lab values mean after someone gets their blood drawn.  Let’s start with your blood pressure.  You are always told numbers but rarely does one understand them.  The top number is called the systolic and the lower number is called the diastolic pressure.  This means the systolic reading is the amount of pressure your heart generates on your arteries as it pumps blood to the rest of the body.  The lower number or diastolic reading is the amount of pressure in your arteries when your heart is at rest.  Did you know that with each beat of your heart, your blood is forced through 60,000 miles of arteries, veins and capillaries?  This can circulate about 2,000 gallons of blood each day.  Your blood pressure can vary from one moment to the next depending on what activity you are engaged in. The recommended normal is 120/80 or lower with the optimal being 115/75.  The higher the blood pressure the higher the risk for cardiovascular disease.  Knowing what your pressure usually runs helps to know if you are having a problem.


Another number that is important to know is your BMI, (Body Mass Index.)  Your BMI is calculated from a person’s height and weight.


            (Divide your weight  / by your [height in inches,] squared then multiply by a set     coversion factor of 703.)                             Ex.  [W ÷ (H)2  ] x 703 = BMI


The result is an indicator for determining body fatness and evaluates risk for disease.  Reasons for using this indicator are that it is inexpensive and very easy to use.  According to the CDC, (Centers for Disease Control), if your BMI is:


            18.5-24.9          this is considered within normal range.

            25.0-29.9          this is considered overweight.

            30 and above    this is considered obese.


BMI’s are very important because are indicators of future possible problems. Consequences of high BMI’s might include possible:

  • Hypertension
  • High triglycerides
  • High cholesterol
  • Increase risk for diabetes, coronary heart disease, cancers, respiratory problems, and stroke to name a few.


Have you ever gone to your physician and had a blood test drawn?  The results come back and your doctor says ‘everything looks normal.’  Have you ever wondered what is in the blood that is normal?  The interpretation of your lab values should only be made by your physician.  I can only provide the guidelines they use for interpretation and mention a few important numbers with which you should be familiar.


Knowing your cholesterol, HDL and LDL number is important because it deals with your cardiovascular status.  Cholesterol is a fatty substance that is necessary for proper cell function.  There are two forms of cholesterol, HDL and LDL.  Your total number for cholesterol should be less than 200mg/dl.  If you have high levels of cholesterol then there is a possibility that you could develop coronary heart disease.  


The good cholesterol is called HDL, (High Density Lipids).  Its purpose is to carry away the cholesterol from the blood vessels to the liver so it can be eliminated.  The higher the lab value for good cholesterol, the lower the risk for heart disease.  It should be noted that proper diet and exercise can also raise the HDL.   A lab value for the HDL should be greater than or equal to 35mg/dl.


The bad cholesterol is called LDL, (Low Density Lipids).  This is the part of the cholesterol that leaves deposits within the vessel walls.  You can help this value if you alter your diet by decreasing your fat intake.  The lab value for LDL should be less than 130mg/dl.


We have talked about cholesterol, HDL and LDL, now let’s look at the cholesterol ratio.  This lab value is obtained by dividing the cholesterol by the HDL result.  The higher the number the greater risk of heart disease.   The lower the lab value of the ratio the lower the risk for heart disease.  Total cholesterol of less than 200 and LDL of 100 or less is optimal according to the National Heart, Lung and Blood Institute.


Everyone should have an idea of what their triglycerides run.  Triglycerides are fat found in nature, consumed in foods and are stored in the form of fat within the body.  This fat provides the body with needed energy.  Higher risk of heart disease has been associated with high fasting triglycerides.  Your acceptable lab values should be less than 200mg/dl.


Do you know what your sugar runs?  This is your fasting glucose lab value.  Glucose is important for the metabolism of the body.  The brain and cell tissues use glucose for energy.  It is absorbed in the small intestines and then is stored as glycogen in the liver.  Glucose is necessary for organs to function and is obtained from the foods we eat.  A fasting lab value should be in a range of 64-128mg/dl.


We have only reviewed a few lab values.  Hopefully, next time you get the results from your physical, you will be able to understand your lab values and what they mean for you and your health.  Sometimes winter can make us complacent so it is important to remember to exercise, rest, eat right and don’t smoke!   As always, if you have any questions or comments, please eMail me.

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