Interlaboratory Comparison

Inter-laboratory studies/comparisons are performed with the aim of evaluating the extent of similarity in the results obtained by different laboratories using the same method. The organization, performance, and evaluation of calibration/test results for the same or similar item by two or more laboratories in accordance with predetermined conditions.

The study typically consists of:

• Planning
• Selection/recru¬itment of laboratories
• Execution according the plan
• Statistical evaluation of results

• If the formal Proficiency testing is not available, then laboratory have to conduct inter-laboratory comparison. Laboratories using spikes and other forms of analytical quality control samples are effectively monitoring the consistency of their own performance. They should have a very good picture of their internal reproducibility. If they perform well on spikes and on any CRMs, they have also every reason to believe that their results are
  accurate.
• Nonetheless, it is in the interest of any laboratory to test this assumption from time to time by exchanging samples with other laboratories and comparing results. Inter-laboratory studies may be informal, in that a group of laboratories will exchange samples on an ad hoc basis, or may be formal exercises organised by a third party who circulates performance indicators. Such exercises are a very effective extension to the internal quality control programme of laboratories.

Inter-Laboratory Comparisons : The organization, performance, and evaluation ofcalibration/test results for the same or similar item by two or more laboratories inaccordance with predetermined conditions.

If the formal Proficiency testing is not available, then laboratory have to conduct inter-laboratory comparison. Laboratories using spikes and other forms of analytical quality control samples are effectively monitoring the consistency of their own performance. They should have a very good picture of their internal reproducibility. If they perform well on spikes and on any CRMs, they have also every reason to believe that their results are accurate. Nonetheless, it is in the interest of any laboratory to test this assumption from time to time by exchanging samples with other laboratories and comparing results. Inter-laboratory studies may be informal, in that a group of laboratories will exchange samples on an ad hoc basis, or may be formal exercises organised by a third party who circulates performance indicators. Such exercises are a very effective extension to the internal quality control programme of laboratories.