Preferred Sample Type


Suitable Specimen Types

  • Serum
  • Li Hep Plasma
5-10 mL blood (minimum sample volume is 60 uL)

Sample Processing in Laboratory


Sample Preparation


Turnaround Time

1 day

Sample Stability



General Information

Calcium ions affect the contractility of the heart and the skeletal musculature and are required for the normal functioning of the nervous system.

Approximately 99% of calcium in the body is stored in bones. Only around 1% of total body calcium is found in plasma. Around half of calcium in plasma exists in the ionised (active) form or is bound to proteins such as albumin (inactive). Total calcium in plasma is therefore affected by the amount of circulating albumin the blood. To account for these changes, an equation can be used to estimate what the total calcium would be if albumin was within reference range limits (usually taken to be 40 g/L).

Adjusted calcium results results are automatically calculated by telepath using the following formula: [ Adjusted Calcium] = [Total Calcium] + 0.014(44.7 – [Albumin]) Note: Adjusted Calcium is not valid for paediatric patients or if acidosis or alkalosis is present. Hypocalcaemia presents itself as tetany and osteomalacia.

Hypercalcaemia is frequently due to an increased mobilisation of calcium from the skeleton and increased intestinal absorption.


Patient Preparation



Prolonged tourniquet use, administration of vitamin D or bendrofluazide can increase calcium concentration

EDTA or citrate contamination will decrease calcium concentration


 ** From 14/08/2020, corrected calcium calculation changed to reflect changes with new analysers and to keep equation in-line with ACB recommendations **

Reference Range

Neonate (<4wks)  2.0-2.7 mmol/L

4wks-16yrs          2.2-2.7 mmol/L

Adult                   2.2-2.6 mmol/L

(Source : Pathology Harmony Recommendations)


  • EQA Scheme?: Yes
  • EQA Status:


Copyright heftpathology 2013, 2014, 2015, 2016, 2017, 2018

HTA licence number is 12366

Protection of Personal Information – Laboratory Medicine comply with the Trust Data Protection Policy and have procedures in place to allow the Directorate and it’s employees to comply with the Data Protection Act 1998 and associated best practice and guidance.

The Trust Laboratories at Heartlands Hospital, Good Hope Hospital and Solihull Hospital were awarded UKAS (United Kingdom Accreditation Service) accreditation to the internationally recognised ISO 15189 standard in May 2015. For a list of accredited tests and other information please visit the test database
Tests not appearing on this scope are either under consideration or in the process of accreditation and so currently remain outside of our scope of accreditation. However, these tests have been validated to the same high standard as accredited tests and are performed by the same trained and competent staff.

For further information contact Louise Fallon, Quality Manager, 0121 424 1235