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Test Code LAB3784 Direct Oral Anticoagulant (DOAC) Screen

Clinical System Name

Direct Oral Anticoagulant (DOAC) Screen

Synonyms

LAB3784

DOAC

DOAC Screen

Direct Xa Inhibitor Screen

Anti-Xa Inhibitor Screen

EPIC Order Code 1230121854

Sample Requirements

Specimen: Whole Blood

Container(s): Lt. Blue/Citrate

Required Vol: one 1.8 mL tube or one 2.7 mL tube (do NOT over or under fill)

Minimum Vol: N

 

Note: This is enough for a PT, PTT, DOAC Screen, and Fibrinogen on the same sample. Preferred method of collection is venipuncture with vacuum fill. Test results are affected by incorrect blood volume. Use of a Vascular Access Device for the collection of coag testing is not recommended.

 

If a venipuncture is not possible and drawing from a line is necessary:

a. Draw from a heparin-free line.

b. If patient has a line infused or flushed with heparin, such as an arterial line or central venous line, waste the following volume:

       A 6-mL waste volume for PIVs, PICCs, temporary venous lines (femoral, jugular) and Baby Broviacs.

       A 12-mL waste volume for all other permanent lines (Hickman, Portacath, HD, tunneled lines).

Blood must be transferred to the Lt. Blue/Citrate tube by use of a blood transfer device to ensure proper fill.

Processing Instructions

Main Campus CPA: Core Technologist will process specimen. Deliver blood directly to Core Coag bench.

 

Reject due to: Clotted, Insufficient quantity (underfill), or Improper collection (overfill).

Spin: Y

Aliquot: Y

Storage location: Core 14 Freezer ( -70 C).

 

Core Technologist: Specimen should be centrifuged within 1 hour of collection. Spin whole blood, remove plasma. Transfer upper 3/4 layer of plasma to plastic tube affixed with large computer label.

 

Off-site collection: Preferred method of collection is venipuncture with vacuum fill. Test results are affected by incorrect blood volume, note the fill line on the tube. Use of a Vascular Access Device for the collection of coag testing is not recommended. If this method is used it requires a 5 mL waste volume; 3 mL for size 2 French catheter or smaller. Blood must be transferred to the Lt Blue/Citrate tube by use of the blood transfer device.

 

Specimen should be centrifuged within 1 hour of collection. Double spin, transfer upper 3/4 layer of plasma to plastic tube affixed with large computer label. Freeze until solid one aliquot of 1.0 mL plasma in plastic tube at -70C (preferred) or -20C.

 

Non-Children's Hospital Off-site collection: Ship completely frozen on dry ice.

 

Children's Regional Clinics: Ship completely frozen in frozen Nalgene Labtop cooler with ice pack inside an insulated soft cooler.

Stability

Specimen Type Temperature Time
Citrated platelet-poor plasma Room temp ≤4 h
  Refrigerated N
  Frozen   -20 C or -70 C ≤3 m

 

Availability

STAT Performed TAT
Y

Daily

 1 h

 

Performing Laboratory

Seattle Children's Laboratory    

 

Department

Department:  Coagulation

Phone Number: 206 987-2617 (Client Services)

 

 

CPT Codes

85520

85670

Methodology

Method: Chromogenic Substrate by STA-R MAX

Analytical Volume: 1 mL plasma

This is enough for a PT, PTT, DOAC Screen, and Fibrinogen on the same sample.

 

Limitations: This assay requires antithrombin III (ATIII) in patient's plasma. Low level of ATIII may underestimate the heparin level.

Results affected by moderate lipemia, moderate hemolysis, and moderate icterus.

High hematocrit greater than or equal to 56% requires a citrate adjusted tube.

Description

The Direct Oral Anticoagulants (DOAC) screen is intended to rapidly identify patients who may be taking direct oral anticoagulants. This information may be useful in making decisions about performing surgery or treating with fibrinolytic agents. Direct Xa Inhibitor Screen will detect direct Xa inhibitors, while the thrombin time will detect direct thrombin inhibitors (DTI).

This screen does not indicate amount of specific DOAC present.

Panel Includes (3 separately reported results):

  • Direct Xa Inhibitor Screen (units/mL)
  • Thrombin Time (TT) (seconds)
  • Anticoagulant Screen Interpretation

 

Direct Xa Inhibitor Screen
(Anti-Xa units/mL)		 Thrombin Time
(TT sec)		 Anticoagulant Screen Interpretation Notes
≥0.10 >25 Heparin presence likely; cannot rule out presence of direct oral anticoagulant. Recommend specimen re-draw and repeat testing.  
<0.10 >25 Direct Thrombin inhibitor (DTI) (e.g. dabigatran) likely present. Order specific drug level if indicated  
<0.10 ≤25 No detectable factor Xa inhibitor or direct thrombin inhibitor present  
0.10 - 0.30 ≤25 Low level factor Xa inhibitor likely present (e.g apixaban, rivaroxaban, edoxaban, enoxaparin, and/or fondaparinux). Order specific drug level if indicated.  Direct Xa inhibitor screen and direct Xa drug level may not be valid after administration of andexanet alfa.
>0.30 ≤25 Factor Xa inhibitor likely present (e.g. apixaban, rivaroxaban, edoxaban, enoxaparin, and/or fondaparinux). Order specific drug level if indicated.  Direct Xa inhibitor screen and direct Xa drug level may not be valid after administration of andexanet alfa.

A significantly elevated Direct Xa result may indicate presence of direct Xa inhibitor (apixaban, rivaroxaban, edoxaban, enoxaparin, and/or fondaparinux), heparin or abnormal fibrin. Order specific drug level if indicated. Presence of direct Xa inhibitor or heparin is excluded with a direct Xa inhibitor level of <0.1 units/mL.
 
A significantly elevated Thrombin Time (TT) result may indicate presence of direct thrombin inhibitor (Dabigatran, bivalirudin, and/or argatroban), heparin or abnormal fibrin. Order specific drug level if indicated. Presence of direct thrombin inhibitor or heparin unlikely with a normal TT.

Therapeutic Range

N/A

Order specific drug level if indicated. 

DOAC activity is reported in Anti-Xa IU/mL (Anti-Xa International Units/mL).

Critical Value

N/A

Critical or elevated results do not necessarily correlate with anticoagulant concentration. Order specific drug level if indicated.

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