This page contains a series of articles about interpreting laboratory tests.
Although there is a lot of general information about how lab tests might be used to assess your health it is very important to interpret them in the light of why they have been taken. This article includes a key to interpreting some of the abbreviations we use when commenting on your blood test results.
ESR or Erythrocyte Sedimentation Rate tests have been available for longer than most other blood tests.
Although the test is now performed more rapidly, in the past a tube of whole blood would have been placed on one end. The blood cells slowly settle to the bottom leaving clear serum above. The ESR is the number of millimetres the blood cells settle in one hour - inflammatory proteins in the plasma make cells settle more quickly.
C-Reactive Protein (CRP) is an 'acute phase protein' and is produced in the body in response to inflammation.
Although we know a little of what CRP does in the body, there are probably quite a lot of influences that are yet to be discovered.
CRP rises quickly in the presence of inflammation or infection so is often used by doctors to see how likely it is that you might have a serious infection. It can also be used to help to distinguish betwween inflammatory and non-inflammatory diseases.
Creatinine (Cr) is used to measure kidney function.
Creatinine is produced by muscle metabolism and removed by the kidneys. In general, the more effectively your kidneys are filtering your blood, the lower your levels of creatinine will be.