Calcium CPT: 82310

Expected Turnaround Time

Within 1 day

Specimen Requirements




1 mL

Minimum Volume

0.5 mL


Red-top tube, gel-barrier tube, or green-top (lithium heparin) tube; do not use oxalate, EDTA, or citrate plasma.


Separate serum or plasma from cells within 45 minutes of collection.

Storage Instructions

Room temperature

Stability Requirements

Temperature Period
Room Temperature 14 days
Refrigerated 14 days
Frozen 14 days
Freeze/thaw/ cycles Stable x 3

Patient Preparation

Morning, fasting sample is desirable, since some diurnal variation exists (which may reflect postural changes).

Patient Information

To screen for, diagnose, and monitor a range of medical conditions.

As part of a routine metabolic panel; when you have symptoms of a disorder, or known presence of one, affecting your kidneys, bones, thyroid, parathyroid, or nerves or when symptoms of significantly increased or decreased calcium concentrations are present; when someone is critically ill, to monitor ionized calcium levels; when someone has certain types of cancer; when someone is being treated for abnormal calcium levels, to evaluate the effectiveness of treatment.

A blood sample is taken by needle from a vein in the arm. If a urine collection is required, a 24-hour urine sample or a timed collection of a shorter duration is obtained. Sometimes a random urine collection may be used, although a timed collection is preferred.

Current practices do not require fasting. You may be instructed to stop taking certain medications, such as lithium, antacids, diuretics, and vitamin D supplements, among others, to ensure the most accurate test results.