Chemical Pathology

Notes

Serum ACE

  • Sarcoidosis is a multisystem inflammatory disease of unknown etiology that manifests as noncaseating granulomas, predominantly in the lungs and intrathoracic lymph nodes.
  • Sarcoidal granulomas produce angiotensin converting enzyme (ACE), however, as a diagnostic tool, measurement of serum ACE levels lacks sensitivity and specificity.
  • Sarcoidosis remains a diagnosis of exclusion and ACE levels are NOT suitable as a diagnostic tool.
  • Serum ACE levels can sometimes be useful to monitor disease activity.
  • Requests for serum ACE will ONLY be processed on patients with diagnosed Sarcoidosis.
  • Serum ACE levels will be falsely low in patients on ACE inhibitors.

CSF ACE:

  • CSF ACE analysis is currently not routinely available as there is little evidence for clinical utility in diagnosis of neurosarcoidosis.
  • CSF ACE has very poor diagnostic sensitivity and specificity for neurosarcoidosis but may occasionally be useful for monitoring disease progression/regression. Levels may be increased if there is blood brain barrier impairment allowing passage of proteins (including serum ACE) across or if there is blood contamination.
  • It is essential to discuss all CSF ACE requests with the Duty Biochemist before performing lumbar puncture to get agreement for sample processing.

Sample requirements

  • Samples will only be processed on patients with diagnosed sarcoidosis.
  • Confirm patient not receiving an ACE inhibitor before proceeding.

For adults, blood taken into a 5mL gold top tube (or rust top for the Acute Unit)

5ml gold tube



For children, blood taken into a 3.5mL rust top tube

3.5ml rust top tube



For monitoring of diagnosed neurosarcoidosis only (following discussion with the Duty Biochemist): request CSF ACE and CSF Protein.

1.0mL, (25 drops) CSF collected into a 30 mL plain universal container.

30ml universal container


Storage/transport

Send at ambient temperature to the laboratory. If unavoidable, samples can be stored refrigerated overnight.

**DO NOT SEND CSF SAMPLES VIA THE AIR TUBE. SAMPLES MUST BE TAKEN BY HAND TO PATHOLOGY RECEPTION**

Required information

Please state especially whether or not the patient is currently taking angiotensin converting enzyme inhibitors.

Turnaround times

Samples are sent for analysis to Kings College Hospital, London, with results expected back within 7 working days.

CSF ACE samples are sent for analysis to Guy's and St Thomas' Hospital, London. Results are expected back with 3 weeks.

Reference ranges

  • 0-18 years: 29-112 IU/L
  • ≥ 19 years: 16 to 85 IU/L

Further information

To learn more about ACE visit Lab Tests Online


Page last updated 29/04/2024