Basic Blood Work

If you have read any of my medical blogs at this point you should have a firm understanding of what internal medicine is and how it differs from other types of primary care.  You also know how to go about finding a good general internist. 

So, you make your appointment; you go see your new doc; you feel comfortable during the visit because this is something you’ve researched and selected for yourself; but you leave the encounter scratching your head about the panel of blood work that your internist ordered.  Let me guess; outside of checking your cholesterol you have little-to-no clue what your doctor is checking for or why.

This is a very common scenario in healthcare.  All too often a rushed physician omits a full explanation of his or her screening and diagnostic tests, while the patient essentially asks no questions until he or she gets a bill 3 weeks later. 

Remember that you must take ownership of your health and use your healthcare provider(s) as a guide throughout the process to obtaining a better you.  Listed below are the common things checked during initial (and in many cases yearly) visits to the doctor and a brief explanation of why they are checked.

Complete blood count aka CBC – checks hemoglobin for anemia and blood indices to further characterize anemias.  A CBC also includes platelets and white blood cells.  If normal, it usually is not repeated on a yearly basis, but it is repeated in the event of a serious infection or potential for blood loss.

Complete metabolic panel aka CMP – checks kidney function, liver function, and basic electrolytes, and screens for diabetes.  CMPs are usually repeated on a yearly basis in older patients or those with chronic medical conditions and are often times done in an abbreviated fashion (basic metabolic panel).

Cholesterol (or Lipid) panel – self-explanatory.  However, your internist is particularly interested in your bad cholesterol (LDL) and, to a lesser extent, your good cholesterol (HDL).  Triglycerides are also included.  You must be fasting for this test.  Again, this is usually repeated on a yearly basis in older adults and in those with heart disease risk factors.

Thyroid function – simply put, the thyroid controls metabolism, and is not uncommonly under- or over-functioning.  This is usually done as a one-time, baseline lab unless it is abnormal or symptoms arise later on.

Age-appropriate and sex-specific screening, such as mammograms, PAP smears, prostate cancer screening, colonoscopies, DEXA scans, and abdominal ultrasounds should also be discussed.  I will go into more detail on each of these in the next issue of Progress Notes.

Other tests such as STD/HIV screening and vitamin D level are also commonly ordered but done in certain populations and circumstances.  Conversely, items such as EKGs, stress tests, and chest x-rays are no longer done on a screening basis.