Test ID: CAS
Calcium, Total, Serum
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Diagnosis and monitoring of a wide range of disorders including disorders of protein and vitamin D, and diseases of bone, kidney, parathyroid gland, or gastrointestinal tract
Method Name A short description of the method used to perform the test
Photometric, O-Cresolphthalein
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
Calcium (Ca)
Calcium, Total
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions: If drawing for more than calcium, total, send first tube drawn.
Additional Information: Patient's age and sex are required.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | Mild OK; Gross reject |
| Lipemia | NA |
| Icterus | NA |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Frozen (preferred) | 21 days |
| Refrigerated | 240 days |
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
The calcium content of an adult is somewhat over 1 kg (about 2% of the body weight). Of this, 99% is present as calcium hydroxyapatite in bones and <1% is present in the extra-osseous intracellular space or extracellular space (ECS). The calcium level in the ECS is in dynamic equilibrium with the rapidly exchangeable fraction of bone calcium. In serum, calcium is bound to a considerable extent to proteins (approximately 40%), 10% is in the form of inorganic complexes, and 50% is present as free or ionized calcium.
Calcium ions affect the contractility of the heart and the skeletal musculature, and are essential for the function of the nervous system. In addition, calcium ions play an important role in blood clotting and bone mineralization.
Hypocalcemia is due to the absence or impaired function of the parathyroid glands or impaired vitamin-D synthesis. Chronic renal failure is also frequently associated with hypocalcemia due to decreased vitamin-D synthesis as well as hyperphosphatemia and skeletal resistance to the action of parathyroid hormone (PTH). A characteristic symptom of hypocalcemia is latent or manifest tetany and ostemeomalacia.
Hypercalcemia is brought about by increased mobilization of calcium from the skeletal system or increased intestinal absorption. The majority of cases are due to primary hyperparathyroidism (pHPT) or bone metastasis of carcinoma of the breast, prostate, thyroid gland, or lung. Patients who have pHPT and bone disease, renal stones or nephrocalcinosis, or other signs or symptoms are candidates for surgical removal of the parathyroid gland(s). Severe hypercalcemia may result in cardiac arrhythmia.
Total calcium levels also may reflect protein levels.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Males
1-14 years: 9.6-10.6 mg/dL
15-16 years: 9.5-10.5 mg/dL
17-18 years: 9.5-10.4 mg/dL
19-21 years: 9.3-10.3 mg/dL
> or =22 years: 8.9-10.1 mg/dL
Reference values have not been established for patients who are <12 months of age.
Females
1-11 years: 9.6-10.6 mg/dL
12-14 years: 9.5-10.4 mg/dL
15-18 years: 9.1-10.3 mg/dL
> or =19 years: 8.9-10.1 mg/dL
Reference values have not been established for patients who are <12 months of age.
Interpretation Provides information to assist in interpretation of the test results
Hypocalcemia:
Long-term therapy must be tailored to the specific disease causing the hypocalcemia. The therapeutic endpoint is to achieve a serum calcium level of 8.0 to 8.5 mg/dL to prevent tetany. For symptomatic hypocalcemia, calcium may be administered intravenously.
Hypercalcemia:
The level at which hypercalcemic symptoms occur varies from patient to patient. Symptoms are common when serum calcium levels are >11.5 mg/dL, although patients may be asymptomatic at this level. Levels >12.0 mg/dL are considered a critical value in the Mayo Health System. Severe hypercalcemia (>15.0 mg/dL) is a medical emergency.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Gadolinium is known to interfere with most metals tests. If gadolinium-containing contrast media has been administered a specimen cannot be collected for 48 hours.
Gadolinium from magnetic resonance imaging (MRI) contrast media may decrease results significantly. Consider testing specimen by spectroscopic (ICP or AA) methodologies for calcium if applicable.
Gadolinium from MRI contrast media may decrease results significantly when testing is performed using this method. If gadolinium-containing contrast media has been administered, a specimen should not be collected for 48 hours. Alternately, other suitable testing options include ion-selective electrode-based assays (eg, CAI/8378 Calcium, Ionized, Serum) or spectroscopic methods (eg, inductively couple plasma and atomic absorption) if available.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Tietz Textbook of Clinical Chemistry, Edited by CA Burtis, CR Ashwood. WB Saunders Company, Philadelphia, 1994
2. Baldwin TE, Chernow B: Hypocalcemia in the ICU. J Crit Illness 1987;2:9-16
Method Description Describes how the test is performed and provides a method-specific reference
Calcium reacts with o-cresolphthalein complexone in alkaline solution to produce a calcium-o-cresolphthalein complexone complex. The intensity of the purple complex formed is directly proportional to the calcium concentration and is measured photometrically at 600 nm.(Package insert: Roche calcium reagent, Roche Diagnostic Corp, Indianapolis, IN, 1999 July)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Sunday; Continuously
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
82310
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| CA | Calcium, Total, S | 17861-6 |
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