Ionized Calcium, Plasma

General Information

Lab Name

Lab Code

PLIC

Epic Ordering

Ionized Calcium, Plasma

Description

If GOLD SST or RED tube is collected/received, see SRICG.

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

Components

Code	Name
PLICA	Ionized Calcium, Plasma
PLICI	Ionized Calcium Info, Plasma

Interpretation

Method: Ion Selective Electrode
Reference Range: See individual components

Ordering & Collection

Specimen Type: Plasma from Lime Green vacutainer
Collection: 3 mL blood in LIME GREEN PST tube. Note time drawn

Unacceptable: Sarstedt or Microtainer
Handling Instructions
Quantity: requested: 1 mL plasma
minimum: 0.5 mL plasma

Processing

Processing: Centrifuge with stopper on within 1 1/2 hours of collection. PST may go directly to bench without aliquotting unless shared specimen.

If Shared, aliquot PLIC into 1 mL syringe, allowing minimal air contact with serum. Tap syringe to expel air bubbles and cap with Leur cap.Plasma is stoppered and re-spun and aliquots made for other tests requested.

Stability: Centrifuged, unopened PST stable 24 hr at 4°C. Once tube is uncapped, plasma sample is stable for 60 minutes.

Performance

LIS Dept Code

Chemistry (CH)

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
UW-MT	Chemistry, Special 206-520-4600 Clinical Lab, Room NW220, University of Washington Medical Center, 1959 NE Pacific street, Seattle, WA 98195

Frequency

Daily, as received

Available STAT?

Yes

Billing & Coding

CPT codes: 82330
LOINC: 12180-6
Interfaced Order Code: UOW4123