Recently there has been substantial attention to a blood test called CRP.  The initials CRP stand for cold reactive protein.  Originally it was found as a blood protein that would continue to react in certain tests at a cold temperature, a laboratory curiosity.  But more recently the protein has been isolated and characterized.  Now very simple laboratory tests can detect it when abnormal amounts appear in the blood.  When first discovered many years ago, this protein was used as a marker to follow patients with rheumatic fever.  I haven't seen a case of rheumatic fever in 30 years and thus the test is no longer useful for that purpose.

     Recently, the test has gained great favor as a means to follow patients with acute infectious diseases such as pneumonia.  This protein can be used to monitor antibiotic levels and the effectiveness of treatment for patients that have pneumonia or abdominal abscesses or kidney infections etc.  It is very useful for that purpose.  Frequently, patients with bad infections will have a very high CRP levels in the range of 20-30 mg% (normal = > .7 mg%).

     In the last several years, researchers have started to use an elevated CRP in the blood as a marker for individuals who are about to have a heart attack.  These researchers noted that people who have heart attacks frequently have a CRP level in the range of 1 to 3 mg%.  Doing research on patients with recent heart attacks, it was found that many of these individuals had high CRP levels for several months to years prior to their heart attack.  A recent article in one of the major medical journals made the point that a high CRP was a better marker for following people with heart disease than was measuring the blood cholesterol.  As you might imagine, doctors are now receiving many calls from patients asking to have their CRP levels checked.  Several individuals have asked me to stop checking their cholesterol and instead follow the CRP.

     A basic rule of medicine maybe stated, "There is no reason to do a diagnostic test with its associated risk, expense and discomfort unless the therapeutic implications of the result will be acted upon."  In other words, if there is to be no action taken in regard to the result of the test, why do it?

     For example, if a blood cholesterol level is checked and found to be elevated, patients are advised to change their diet and exercise more.  This is very infrequently effective.  Often times patients will try for two to six months to get cholesterols down with a diet and exercise program and then will start a medication.  Once the medication is started, other blood tests are done to monitor the effectiveness of the drug and be sure that side effects are not occurring.  Thus there is action being taken based upon the results of a blood cholesterol test.

     Another very simple test that patients can do themselves is to measure their blood pressure.  If the blood pressure is found to be consistently above 130/80 or more, patients are advised to decrease the salt in their diet, to control their weight, exercise more, or to get help with sleep or pain problems.  When these measures are ineffective, medications might be used.  Continuing to monitor the person's blood pressure is a test.  It is used to insure that the medication being used is effective and thus the test is being acted on. The same considerations are involved in checking blood sugars in people that are diabetic or are cursed with hereditary factors predisposing them to diabetes.

     In regard to the CRP blood test, it is now well established that individuals with chronic low-level elevations of CRP have more heart attacks than people whose CRP levels are normal.  The problem in using this test revolves around what one might do if a test returns abnormal.  Specifically, we know that the "statin" family of cholesterol medications lowers the CRP in patients that have slight elevations.  We know that stopping smoking lowers the CRP in patients that have slight elevations.  We have learned that controlling blood sugars, lowering blood pressure, improving the quality of sleep, stopping pain problems and dealing with stress problems all lower CRP levels.  Just in case you've never noticed, this is advise that is given to every person that walks through the door whether they have high CRP levels or not.  So why do we need to do a CRP blood test?

     Perhaps it's useful as an "attention getter".  Perhaps it is useful as a reminder for individuals who continue to struggle with life style changes.  But doing a CRP blood test is not a replacement for following blood cholesterols, monitoring blood pressures, monitoring blood sugars, and dealing with the various problems as above.  There is no magically hidden information in a CRP that isn't also available from all the various other steps that we take to monitor therapeutic interventions.

     Along the same line, I recently had a person come in with severe back pain.  They wanted an MRI scan done of their back to see what was wrong.  I inquired as to whether or not the person would consider surgical intervention if the MRI scan indicated the need for same.  The person said, "No, their back pain was not severe enough to consider surgery."  I then explained that there wasn't a reason to do the MRI scan unless the person was willing to follow the therapeutic suggestions that would come from that scan.  I indicated that since the person wanted to pursue conservative measures such as physical therapy, local heat to the back, rest, and avoidance of strain, these steps could be undertaken without performing an MRI scan.  The person became very irate when he found that the insurance company wouldn't cover the expense of his MRI scan.  An MRI scan done after the failure of conservative treatment in a person who would consider surgical intervention if it were indicated does indeed benefit from having the MRI scan done.  But if the decision is already made that they would not do surgery no matter what the result of the MRI scan was, then understand that there is no reason to do the MRI scan.

     Stated simply, "If you are going to do the test, then you ought to abide the result.  If the decision to treat a certain way is already made, then there is no reason to do the test."   This is a rule that comes up again and again and is frequently violated.  Insurance companies and medicare are becoming more sensitive to these problems refusing to pay for tests that they consider unnecessary.  Misunderstanding and consternation can be avoided by utilizing the considerations above.  The healthcare professionals at your local clinics are well aware of what laboratory and other diagnostic tests are useful and indicated in a given situation and can help in making decisions.