1:1 Mix_PTT

General Information

Lab Name

1:1 Mix_PTT

Lab Code

PTTX1P

Epic Name

1:1 MIX_PTT

Description

A Partial Thromboplastin Time (PTT) mixing study is ordered to evaluate the prolongation of PTT only. It is used to distinguish the cause of prolonged PTT due to factor deficiency or inhibitor. A 1:1 mix of the patient's plasma and normal pooled plasma is performed and the PTT is measured again. If the PTT corrects, this suggests a factor deficiency. If the PTT does not correct, this suggests presence of an inhibitor. A mixing study interpretation may direct further coagulation testing.

Synonyms

Mix-PTT 1:1, Partial Thromboplastin Time-MIX

Components

Code	Name
PTTMX1	1:1 Mix_PTT
PTTPT	PTT Patient
PTTNOR	PTT Normal Pool
PTTMIX	PTT 1:1 Mix Immediate
INCMIX	PTT 1:1 Mix Incubated
PTTCOM	PTT 1:1 Mix Comment
XMIX	1:1 Mix, 2nd tube

Interpretation

Method: Clot based
Reference Range: See individual components
Ref. Range Notes: For interpretation contact the Lab Med Resident on-call through the paging operator at 206-598-6190.

Ordering & Collection

Specimen Type: Blood
Collection: Two 3 mL plastic BLUE TOP (Citrate) Tubes
Handling Instructions: The Laboratory MUST process specimen, within 6 hrs of blood collection.

Processing

Receiving Instructions: UW-MT and HMC: Take specimen to the Coag bench for processing.

Outside Laboratory: Centrifuge for 10 minutes, remove plasma & re-spin plasma for another 10 minutes. Decant & Freeze plasma (minimum 2.0 mL) @ -20°C to -80°C. Send frozen on dry ice.

Misc Sendout

Performance

Lab Department

Frequency

Daily

Available STAT?

Yes, Daily 7 am – 10 pm. For other times, contact the Lab Medicine Resident for approval.

Performing Location(s)

HMC	Coagulation 206-520-4600 325 9th Ave, Rm # GWH-47, Seattle, WA 98104-2420
UW-MT	Coagulation 206-520-4600 Clinical Lab, Room NW220, University of Washington Medical Center, 1959 NE Pacific street, Seattle, WA 98195

Billing & Coding

CPT Codes: 85730, 85732
LOINC: 18720-3
Interfaced Order Code: UOW4073