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Test Code LAB4257 Anti-Xa Assay, UFH

Specimen Type

Blue top tube (buffered 3.2% liquid sodium citrate) filled to the indicator with whole blood or Sodium Citrate Plasma removed from cells.

Specimen Volume

3mL Blue top (3.2% Sodium Citrate)
5mL Blue top (3.2% Sodium Citrate)
1mL Blue top (3.2% Sodium Citrate)
500uL (minimum) Sodium Citrate Plasma spun and removed from cells.

Turnaround Time

STAT: 1 hour
Routine: 4 hours

Test Schedule

Daily

Sample Stability

Room temp: 1 hour unspun, 2 hours spun.  Platelet poor plasma is required.

Frozen samples are stable for 2 weeks at -20C or 12 months at -70C.

Method

Anti-Xa Chromogenic

Reference Ranges

Anti-Xa, UFH: ≤0.10 IU/mL 

Critical Range: >1.0m IU/mL

Synonyms

Unfractionated Heparin, Anti-Xa; Heparin

CPT Codes

85520

Collection Instructions

Fill a Blue Top Container to the Indicator mark on the tube. Overfilled and underfilled tubes are not acceptable.

Specimen Processing

Samples should be centrifuged and run within one hour. If time interval between drawing and testing exceeds 1 hour, process sample to create platelet poor plasma  (centrifuge specimen, separate plasma, centrifuge again, separate into plastic tube) and  freeze at -20C. Platelet poor plasma is stable refrigertaed for 2 hours, Frozen (-20 C) for 2 weeks, or Frozen (-70 C) for 12 months.

Rejection Criteria

Severely hemolyzed specimens, clotted samples. Overfilled and underfilled tubes are not acceptable