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Calcium

Ca

Test Codes

Antrim #15619, EPIC: LAB5025, CA

Department

Chemistry

Instructions

Note: Blood should be obtained with as little venous stasis (i.e. tourniquet time) as possible. Prolonged use of a tourniquet may result in false elevation of calcium.

Specimen Collection Criteria

FOR EC AND INPATIENT SAMPLE COLLECTION ONLY:

Preferred Sample:  One Light Green (Mint) Top Plasma Separator Tube (PST). (Minimum Whole Blood: 4.0 mL) 

Acceptable Sample:  One Gold Top SST (Minimum Whole Blood: 4.0 mL) 

Do NOT use Dark Green-top Lithium or Sodium Heparin tubes.

FOR PHYSICIAN OFFICE/OUTREACH SAMPLE COLLECTION:

COLLECT:  One Gold Top SST (Minimum Whole Blood:  4.0 mL) 

Contact Laboratory for acceptability of other tube types.
See Minimum Pediatric Specimen Requirements for Microtainer^® collection.

Physician Office/Draw Specimen Preparation

Let SST specimens clot 30–60 minutes then immediately centrifuge to separate serum from cells. Refrigerate (2–8°C or 36–46°F) the centrifuged SST tube within two hours of collection. (Minimum: 0.5 mL)

Preparation for Courier Transport

Transport: Centrifuged SST tube, refrigerated (2–8°C or 36–46°F). (Minimum: 0.5 mL)

Rejection Criteria

Moderate to grossly hemolyzed specimens.

Red-top tubes with serum not separated from cells within two hours of collection.

In-Lab Processing

Let SST specimens clot 30-60 minutes. Centrifuge SST tubes and Microtainers^® to separate serum from cells. Deliver immediately to the appropriate testing station.

Storage

Specimen Stability for Testing:

Centrifuged SST Tubes and Microtainers^® with Separator Gel
Room Temperature (20–26°C or 68-78.8°F): 2–4 hours
Refrigerated (2–8°C or 36–46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Red-top Tubes and Microtainers^® without Separator Gel
Room Temperature (20–26°C or 68–78.8°F): 2–4 hours
Refrigerated (2–8°C or 36–46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable

Serum Specimens (Pour-Overs)
Room Temperature (20–26°C or 68–78.8°F): 2–4 hours
Refrigerated (2–8°C or 36–46°F): 7 days
Frozen (-20°C/-4°F or below): 7 days

Specimen Storage in Department Prior to Disposal:

Refrigerated (2–8°C or 36–46°F): 7 days

Laboratory

Canton Chemistry Laboratory
Dearborn Chemistry Laboratory
Farmington Hills Chemistry Laboratory 
Grosse Pointe Chemistry Laboratory 
Lenox Main Laboratory
Livonia Main Laboratory
Royal Oak Automated Chemistry Laboratory 
Troy Chemistry Laboratory
Taylor Chemistry Laboratory
Trenton Chemistry Laboratory
Wayne Chemistry Laboratory 

Performed

Sunday – Saturday, 24 hours a day.
STAT results available within 1 hour of receipt in the Laboratory.
Routine results available within 24 hours.

Reference Range

Age	Range (mg/dL)
0 – < 1 Year	8.5 – 11.0
1 – 18 Years	9.2 – 10.7
19 Years – Adult	8.5 – 10.5

Test Methodology

Spectrophotometry or Indirect Potentiometry.

Interpretation

• High calcium levels can occur in a variety of conditions including primary hyperparathyroidism, malignancy, granulomatous disorders (e.g. sarcoidosis), milk-alkali syndrome, excess intake of vitamin D or A, hyperthyroidism, with thiazide treatment, and in familial hypocalciuric hypercalcemia.
• Low calcium levels can occur with chronic renal failure, vitamin D deficiency, malabsorption, hypomagnesemia, pancreatitis and hypoparathyroidism.

Clinical Utility

The quantitative determination of calcium aids in the diagnosis and management of a variety of diseases including those involving the parathyroid glands, bone and kidneys.

CPT Codes

82310
LOINC: 17861-6

Contacts

Last Updated

11/8/2022