What is this test?
Total calcium measures protein-bound and free calcium together. Calcium supports bones, nerves, muscles and heart function, and the total value is influenced by albumin.
Why might it be ordered?
- To investigate bone, kidney or parathyroid concerns or symptoms of abnormal calcium.
- To monitor a condition or medicine that affects calcium balance.
What sample is needed?
A blood sample is required. The laboratory chooses the correct tube and handles the sample for this test.
How should you prepare?
Ask the laboratory whether you need to fast or attend at a particular time. Do not stop or change medicines or supplements unless your clinician tells you to.
How should you understand the result?
Albumin can make total calcium appear high or low without the biologically active fraction changing. Corrected or ionized calcium may be useful in selected situations.
Sources and editorial status
This patient-facing text is an editorial draft. It should be approved by a laboratory physician before official publication.