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Ionized Calcium SYSTEMIC CRRT

Continuous Renal Replacement Therapy

Test Codes

EPIC: LAB5341, SOFT: CAIOC

Instructions

This test is only available for order on inpatients.

Specimen Collection Criteria

Collect: Arterial or venous whole blood specimen in a heparinized blood gas syringe from a systemic IV access line distal from the calcium chloride IV infusion. The specimen should NOT be drawn from sites immediately pre-filtration (would be diluted and contain some citrate), or immediately post-filtration (where the replacement calcium infusion is).

• This specimen is collected by nursing staff only.
• A 1 mL or 3 mL plastic syringe containing dry heparin is preferred for specimen collection.
• At least 1-2 mL (0.3 mL for pediatric patients) of blood is needed to ensure proper assay.
• For specimens collected by syringe, any air bubbles present in the syringe must be immediately expelled, the needle removed, and the syringe tightly capped. The syringe is rolled between the palms of the hands to ensure mixing.
  • Note: The Radiometer safePico Self-fill^TM syringe has a metal ball to ensure homogeneous mixing when the syringe is rolled between the palms of the hands.
• The specimen must be properly labeled.
• Place on wet ice for transport. Ice and Specimen must be kept separated.
  • Suggested: Place specimen in front pocket of the biohazard bag. Place ice in zip lock section of biohazard bag.
• The specimen must be transported immediately to the STAT Laboratory (Royal Oak) or to the Chemistry Laboratory (Troy and Grosse Pointe). 

Rejection Criteria

Specimens not collected and processed as indicated.

Inpatient Specimen Preparation

The specimen must be transported STAT, on wet ice, to the STAT Laboratory (Royal Oak) or Chemistry Laboratory (Grosse Pointe and Troy).

In-Lab Processing

Immediately analyze the whole blood, heparinized, iced specimen upon receipt.

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): Unacceptable
Refrigerated (2-8°C or 36-46°F): 1 hour
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

Specimens are disposed within 8 hours of testing.

Laboratory

Grosse Pointe Chemistry Laboratory
Royal Oak STAT Laboratory
Troy Chemistry Laboratory

Performed

Sunday – Saturday, 24 hours a day.
Results available within 15 minutes of receipt in the Laboratory.

Reference Range

Target Range: 4.48-5.28 mg/dL.

Test Methodology

Potentiometry.

Interpretation

Calcium chloride rate titrations are determined by the systemic ionized calcium level (mg/dL), drawn from the patient via arterial or peripheral line. It should NOT be drawn from sites immediately pre-filtration (would be diluted with fluid and contain some citrate), or immediately post-filtration (where the replacement calcium infusion is). The systemic ionized calcium will be determined at baseline stat and Q3hrs x 2, then Q6hrs after initiation of citrate use with CRRT.

Clinical Utility

For patients in the ICU receiving regional citrate anticoagulation with continuous renal replacement therapy, calcium chloride is infused into the Afferent line (blood going back into patient) to normalize the patient's systemic calcium level, after chelation with citrate, and intentional hypocalcemia regionally in the CRRT circuit. Calcium chloride infusion rate titrations are determined by systemic ionized calcium levels (mg/dL).

CPT Codes

82330

Contacts

Last Updated

4/28/2020