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Clinical Chemistry: transition to new laboratory equipment

As part of a major investment project for Pathology at RCHT, the Clinical Chemistry Laboratory changed suppliers and upgraded most of their equipment from Monday 17th Sept 2018

What did NOT change:

Tests can be requested in the same way and results will be available as before. Referred tests will not change.

What did change:

Many reference ranges changed, therefore All RESULTS MUST BE INTERPRETED IN THE LIGHT OF ANY NEW REFERENCE RANGES. These are available alongside the results from the change of equipment.

Troponin cardiac marker moved from hsTnT to hsTnI. As before all results MUST be interpreted in the light of the clinical information and a normal hsTnI does not exclude ACS. The new cut offs values are given below:


Lower limit of Detection                              <2 ng/l

New cut off - Women                                   >15 ng/L Associated with cardiac damage

New cut off - Men                                         >34 ng/L Associated with cardiac damage

Cut off men and women (10x99 centile)    >260 ng/l MI likely


Endocrinology tests

Short Synathen test: Adrenal insufficiency is indicated by a cortisol of <440 at 30 mins post Synacthen.

Some new ranges are be markedly different, for instance Cortisol, FT4 and TPOAB, however the new reference range or cut off will account for that difference.

Eg Free T4 Existing ref range (12 - 22 ) New reference range (10.3 - 17.0)


CEA and Ca125 did not see a significant change. There is be a big bias change for the new HCG assay making longitudinal interpretation of the tumour marker more difficult. The bias is specified on the results but if there is a clinical need to check the results with the previous method that can be arranged.


Duty Biochemist 01872 253047

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