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Test Code COAG MIX COAG MIX PANEL

Clinical System Name

Coagulation Panel with Reflex to 1:1 Mix
 

Synonyms

1:1 Mix
50:50 Mix
Mixing Study

Coag Mix Panel

Description

Mixing studies may be indicated when a PT or APTT test result is prolonged, whether the prolonged result was due to factor deficiency or the presence of an inhibitor. If the abnormality was the result of factor deficiency, the 1:1 mix with Pooled Normal Plasma will shorten the clotting time of the assay ("correct it") to within the normal reference range for the assay. If the abnormality was due to the presence of an inhibitor, the clotting time obtained on the 1:1 mix may shorten or ‘correct' only partially or not at all. APTT mixes are incubated for 1 hour with Pooled Normal Plasma to help detect factor VIII inhibitors.

Fibrinogen and Thrombin Time are run as part of this panel to rule out other causes for prolonged PT or PTT, such as hypofibrinogenemia, or the presence of heparin.

Sample Requirements

Specimen: Whole Blood

Container(s): Lt Blue/Citrate

Preferred Vol: 2 x 1.8 mL

Minimum Vol: N

 

Note:  Preferred method of collection is venipuncture with vacuum fill.  Test results are affected by incorrect blood volume, note fill line on 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 trasferred to the  Lt Blue/Citrate tube by use of a  blood transfer device to ensure proper fill. 

Specimen should be centrifuged within 1 hour of collection.

 

Processing Instructions

Reject due to: Clotted, Hemolyzed, Insufficient quantity, and  Improper collection.

Spin:N

Aliquot N

Temp:RT

Storage location: Core 6 Freezer  ( -70 C).

 

Note: Deliver blood to Core Coag bench.  Coag Technologist will process. 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 2 aliquots of 1.0 mL plasma in plastic tubes at -70C.

Ship frozen on dry ice.

Stability

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

 

Availability

STAT Performed TAT
Y

Daily

3 h

 

Performing Laboratory

Seattle Children's Laboratory    

 

Department

Department:  Coagulation

Phone Number: 206 987-2578

 

 

 

Reference Range

 

APTT

 

Newborn – 3months

 

25 – 40 seconds

 

3 months and older

 

25 - 35 seconds

 

PT

 

Newborn – 3 months

 

12.5 – 17.0 seconds

 

3 months and older

 

12.5 – 15.2 seconds

 

Fibrinogen

 

All ages

 

230 – 450 mg/dL

 

Thrombin Time

 

Newborn – 3 months

 

14 – 30 seconds

 

3 months and older

 

14 – 17 seconds

 

 

 

Methodology

Method:  Electromagnetic mechanical clot detection system by STA® - Compact Analyzer

Analytical Volume: 1 mL plasma

 

 

 

Limitations:

Mixing studies will only be run if the PT or APTT results exceed the normal reference range for the assay. The Coag Mix Panel may be added on to a previous coagulation specimen provided there is adequate sample remaining. If there is not enough sample remaining for the entire mix panel, a mixing study alone on the affected analyte will be attempted. Samples that do not contain enough remaining plasma to complete at least a mixing study must be recollected and the Coag Mix Panel performed on the new specimen.

 

Method is affected by improper collection, processing and storage.

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

 

CPT Codes

85610

85611

85730

85732

85670

85384

 

Critical Values

 

APTT

 

≥ 150 seconds (all ages)

 

PT

 

> 30 seconds (all ages)

 

Fibrinogen

 

< 60 mg/dL

 

Thrombin Time

 

None defined