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HomeLab Services GuideTests
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Overview
ข้อมูลทั่วไป Specimen
ข้อมูลสิ่งส่งตรวจ Performance
ข้อมูลการทดสอบ Clinical & Interpretation
ข้อมูลทางคลินิก
 
Test Code (รหัสการทดสอบ):
PT
Order Name (ชื่อการทดสอบ):
PT (Prothrombin Time)
 
Specimen / Container (สิ่งส่งตรวจ/ภาชนะ):
Blood/ Sodium citrate tube (Sodium Citrate 3.2% anticoagulant, Blue top) 3 mL, 1 tube
 
Turnaround Time (ระยะเวลารอผล):
Collected specimen to report within 1 hour
 
Useful For (ประโยชน์การทดสอบ):
The test of Prothrombin time (PT) is the test to find the abnormality of blood clotting factor in Extrinsic pathway such as Factor II, V, VII and Factor X which can be guideline for diagnostic and monitoring the care of Oral anticoagulant
 
Methodology (วิธีการทดสอบ):
Clotting assay
 
Test List In Profile (การทดสอบใน Profile):
PT/INR
 
AliasesName (ชื่อเรียกอื่นๆ) :
PT
Pro Time
PT/INR
Protime INR
Prothrombin Time and International Normalized Ratio (PT/INR)
 
 
 
Test Code (รหัสการทดสอบ):
PT
Order Name (ชื่อการทดสอบ):
PT (Prothrombin Time)
 
Collection Specimen Or Container (สิ่งส่งตรวจ/ภาชนะ):
Blood/ Sodium citrate tube (Sodium Citrate 3.2% anticoagulant, Blue top) 3 mL, 1 tube
 
Specimen Testing Type (สิ่งส่งตรวจที่ใช้ในการทดสอบ):
Citrate plasma, minimum volume 0.5 mL
 
Sub Mission Container (ภาชนะส่งตรวจ):
Plastic tube
 
Rejection Criteria (เกณฑ์ปฏิเสธสิ่งส่งตรวจ):
Hemolysis: Hemoglobin >500 mg/dL
Lipemia: Triglyceride >1,000 mg/dL
Icterus: Bilirubin >30 mg/dL
Other: Clotted specimen will be rejected.
 
Specimen Stabillity (ความคงตัวของสิ่งส่งตรวจ):
Specimen Type Temperature Time
Whole blood, Sodium citrate Room temperature, 18oC to 25oC 4 hours
Plasma, Sodium citrate Room temperature, 18oC to 25oC 4 hours
  Refrigerated, 2oC to 8oC 4 hours
  Frozen, -20oC 2 weeks
  Frozen, -70oC 1 year
 
 
 
Test Code (รหัสการทดสอบ):
PT
Order Name (ชื่อการทดสอบ):
PT (Prothrombin Time)
 
Method detail (วิธีการทดสอบ):
Clotting assay
 
Schedule (ตารางการทดสอบ):
Tested Daily (24 hours)
 
Turnaround Time (ระยะเวลารอผล):
Collected specimen to report within 1 hour
 
Performing Location (หน่วยงานที่ทำการทดสอบ):
Hematology, Laboratory Department Tel. 17254
 
Specimen Retention Time (ระยะเวลาเก็บสิ่งส่งตรวจ):
14 days
 
 
 
Test Code (รหัสการทดสอบ):
PT
Order Name (ชื่อการทดสอบ):
PT (Prothrombin Time)
 
 
Clinical Information (ข้อมูลทางคลินิก):
This assay is used to monitor oral anticoagulant therapy to maintain a patient in a safe therapeutic range.

In the absence of oral anticoagulant therapy, a prolonged prothrombin time indicates deficiency of 1 or more factors (I, II, V, VII, or X) or the presence of a coagulation inhibitor.

The prothrombin time is also reported as the INR (International Normalized Ratio), based on the ISI (International Sensitivity Index) assigned to the thromboplastin and coagulometer. This assay is used for monitoring "stable" oral anticoagulation.
 
Reference Value (ค่าอ้างอิง):
The reference interval can be viewed from the result report of the HIS system.
Remarks: The test value depends on lot number of reagent.
 
Interpretation (การแปลผล):
  1. PT, which lasts longer than normal range, is found in patient who lacks or abnormal blood clotting in extrinsic pathway and common pathway such as factor VII, X, V, II and fibrinogen. Besides that, patient got something resisted toward blood clotting factor can make the PT result longer than normal as well.
  2. INR (International Normalized Ratio) INR = (Patient’s PT / Geometric mean of PT normal range)ISI Geometric mean calculated from 40 normal PT results which calculated by Microsoft exel. ISI (International Sensitivity Index) is attached in the insert sheet and different in each lot reagent. So, when the lot of reagent was changed, or changing the analyzer machine, ISI value should be changed for accurate INR value which is important when Anticoagulant therapy was givento patient, therapeutic range of INR level should be 2-3. In case INR is less than 2 that means physician gave less Anticoagulant which cannot dilute fibrin clot in the body. If INR value is more than 3, it means that Anticoagulant has been over taken and patient may got bleeding.
  3. The following condition and disease which can make PT’s value longer than normal: Liver failure (cirrhosis, hepatitis, jaundice), Vitamin K deficiency, Treatment with vitamin K antagonistsTreatment with preservation such as sodium warfarin (Coumadin), dicumeral, etc., Hemorrhagic disease of the newborn, Intestinal reabsorption disorder, Fibrinolysis and DIC.
 
Clinical Reference (เอกสารอ้างอิง):
  1. Manufacturer’s reagent package insert , RecombiPlasTin 2G,HemosILTM, Instrumentation Laboratory Company - Bedford, MA 01730-2443 (USA), Instrumentation Laboratory SpA - V.le Monza 338 - 20128 Milano (Italy) ; 09/2016
  2. https://www.mayocliniclabs.com (Retrieved: 22 Jan 2019)