Calcium (Ionized), Whole Blood

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General Information

Lab Name
Calcium (Ionized), WBLD
Lab Code
WIC
Epic Ordering
Calcium, Ionized, Whole Blood
Description

Direct vs. Reflexive Ionized Calcium Testing

Calcium testing is useful for investigating disorders involving the parathryoid-vitamin D-calcium endocrine system. Testing is indicated for patients with documented or suspected derangements in this system, but there is little evidence to suggest that screening unselected patients with calcium testing is useful, even in critically ill patients. Standing orders for monitoring ionized or total calcium and replacing with calcium gluconate in patients WITHOUT documented or suspected calcium disorders is unlikely to be of benefit, and may lead to poorer outcomes (see references below).

In order to detect clinically-significant hypo- and hyper-calcemia in hospitalized patients, please use Calcium (Reflexive Ionized) [ICAR] or Basic Metabolic Panel with Reflexive Ionized Calcium [BMPICR]. In this test panel, a patient receives a total calcium test first, and if the result is <8 mg/dL or >10.2mg/dL, an ionized calcium test is performed on the same plasma sample. The test panel was developed as an alternative to daily ionized calcium testing in patients hospitalized at UW and Harborview Medical Centers, a largely unnecessary practice that was associated with excessive calcium therapy.

Calcium (Ionized), Whole Blood [WIC] is intended for patients in whom a calcium metabolic derangement has ALREADY been detected and in whom the calcium concentration needs to be followed, i.e. in post-surgical hypoparathyroidism. Additionally, nonreflexive ionized calcium testing is useful when the total calcium is not expected to correlate well with ionized calcium concentrations, i.e. hypo- or hyper- proteinemia or albuminemia, altered pH, and high concentrations of calcium binding substances like citrate anticoagulants.

Synonyms
Non-Reflexive Ionized Calcium
Components

Interpretation

Method

Electrochemistry

Reference Range
See individual components

Ordering & Collection

Specimen Type
Whole Blood
Collection

Arterial or Venous blood collected into a balanced heparinized syringe such as the 2 mL Radiometer PicoTM or 3 mL Smiths Portex Pro-Vent syringes. Pediatric draw: Arterial or Venous blood collected into a 1 mL balanced heparinized syringe. Unacceptable: any microtainer tube

Handling Instructions

Needles must be removed from syringes and replaced with caps before sending to the lab. No air bubbles. Transport to Lab Immediately. Note: The Laboratory MUST assay specimen within 30 minutes of blood collection.

Quantity
requested: Full Syringe
minimum: 0.20 mL

Processing

Processing

Take syringe to Blood gas bench immediately

Performance

LIS Dept Code
Chemistry, Whole Blood (CHW)
Performing Location(s)
HMC Chemistry, Automated
206-520-4600

325 9th Ave, Rm # GWH-47, Seattle, WA 98104-2420
UW-NW Main Lab
206-668-1344

UW Medical Center – Northwest
1550 N 115th Street, A200
Seattle, WA 98133
FHCC Fred Hutch Alliance Lab
206-606-1088

825 Eastlake Ave, Seattle, WA 98109
UW-MT Chemistry, Blood Gas
206-520-4600

Clinical Lab, Room NW220,
University of Washington Medical Center,
1959 NE Pacific street, Seattle, WA 98195
Frequency
Daily
Available STAT?
Yes

Billing & Coding

CPT codes
82330
LOINC
47596-2
Interfaced Order Code
UOW848