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Calcium, Ionized, Post Filter CRRT

Continuous Renal Replacement Therapy

Test Codes

EPIC: LAB1231110, Beaker: CAIOP

Department

Chemistry

Instructions

This test is only available for order on inpatients.

Specimen Collection Criteria

Collect: Whole blood specimen in a heparinized blood gas syringe from the post-filter access port on a CRRT machine.

• This specimen is collected by nursing staff only.
• A 1.0 mL or 3.0 mL plastic syringe containing dry heparin is preferred for specimen collection.
• At least 1.0-2.0 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 Laboratories. 

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

Dearborn Chemistry Laboratory
Farmington Hills Chemistry Laboratory 
Grosse Pointe Chemistry Laboratory 
Royal Oak STAT Laboratory
Troy Chemistry Laboratory
Taylor Chemistry Laboratory
Trenton Chemistry Laboratory
Wayne Chemistry Laboratory

Performed

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

Reference Range

Target Range: 1.00 - 1.60 mg/dL.

Test Methodology

Potentiometry.

Interpretation

For patients in the ICU receiving regional citrate anticoagulation with continuous renal replacement therapy, citrate infusion rate titrations are determined by post-filter ionized calcium levels (mg/dL), drawn from the return (Afferent) line of the CRRT filter set. The post-filter ionized calcium will be determined at baseline stat and Q3hrs x 2, then Q6hrs after initiation of citrate use with CRRT. For the Laboratory to be able to run STAT, the samples are drawn by the nurse in a blood gas syringe, labeled "ionized calcium POSTFILTER-CRRT", put on ice, and sent to the STAT Laboratory (Royal Oak) or Chemistry Laboratory (Grosse Pointe and Troy). This is necessary to ensure a faster result time, and to assign a normal/target range of 1.0-1.6 mg/dL, distinct from routine, systemic ionized calcium levels (4.48-5.28 mg/dL).

Clinical Utility

For patients in the ICU receiving regional citrate anticoagulation with continuous renal replacement therapy, citrate infusion rate titrations are determined by post-filter ionized calcium levels (mg/dL), drawn from the return (Afferent) line of the CRRT filter set.

CPT Codes

82330
LOINC:  17864-0

Contacts

Last Updated

1/15/2025