In this section
By Jo Adaway
Consultant Clinical Scientist, Biochemistry
March 2025
Biochemistry results from Primary Care are reported using the ICE system and are also visible in the Greater Manchester Care Record. Reference ranges are associated with these results, and many results outside the reference range will be flagged in the system. Exceptions to this are tests whose expected result may depend on multiple factors and the reference range is provided as an interpretative comment. Such results will not flag regardless of the result, so it is important that all results are reviewed.
We also have critical limits for some tests, and if the results fall outside these limits, we will communicate these results directly by phone to the requesting GP surgery, or if out of hours, to the appropriate covering service. These critical limits are for results that may signify a pathophysiological state that might be life threatening or of immediate clinical significance. The limits are based on Royal College of Pathologists guidelines with some locally agreed adjustments and additions.
The critical or phoning limits for results for adult patients are listed below.
| Analyte | Units | Below or equal to | Above or equal to |
| AKI alert | NA | AKI stage 3 | |
| Albumin | g/L | 10 | NA |
| ALT | U/L | NA | 500 |
| AST | IU/L | 500 | |
| Bicarbonate | mmol/L | 10 | |
| Calcium (adjusted) | mmol/L | 1.8 | 3.5 |
| CK | U/L | NA | 5000 |
| Cortisol (unless patient documented to be on steroid replacement) | nmol/L | 100 | NA |
| Creatinine (if no AKI stage available) | µmol/L | NA | 354 |
| CRP | mg/L | NA | 300 |
| Glucose | mmol/L | 2.5 | 25 |
| Lipase | U/L | NA | 300 |
| Magnesium | mmol/L | 0.4 | NA |
| Phosphate | mmol/L | 0.3 | NA |
| Potassium | mmol/L | 2.5 | 6.5 |
| Sodium | mmol/L | 120 | 160 |
| Troponin T | ng/L | NA | 15 |
| Urea (unless patient is on dialysis) | mmol/L | NA | 30 |
Other results may sometimes be phoned to the GP surgery by the Duty Biochemist, based on the clinical details available and their clinical judgement.
If you have any questions about these phoning limits, please contact jo.adaway@mft.nhs.uk or timothyjames.morris@mft.nhs.uk