At a glance
| Analyte | Prothrombin time / INR |
|---|---|
| Also called | Prothrombin time, PT, INR, Protime |
| Method | Clotting, thromboplastin-based |
| Sample type | Citrated plasma |
| Panel | Coagulation |
| Discipline | Coagulation |
| Brand | Mindray |
What PT Reagent measures
The prothrombin time measures how long citrated plasma takes to clot once a thromboplastin reagent is added, and it interrogates one arm of the clotting cascade. Its most familiar use is monitoring patients on warfarin, and for that purpose the raw seconds are converted to an International Normalised Ratio, a calculation that exists specifically so a result produced in one laboratory with one reagent lot can be compared with a result from another. That conversion depends on a sensitivity index which is specific to the reagent lot and is supplied with it, so entering the correct index for each new lot is not administrative housekeeping but part of producing a valid result. PT is also used in pre-operative screening and in the assessment of liver synthetic function.
How Philippine laboratories run it
Pre-operative clearance is the largest single driver of PT volume in Philippine hospitals, which ties demand to the elective surgical schedule rather than to the outpatient laboratory rhythm, and it makes turnaround the specification that matters: a delayed PT delays a theatre list. Warfarin monitoring adds a steady stream of repeat testing on a known patient group. Laboratories should hold cover for stat requests separately from routine volume, and should have a documented process for entering the new sensitivity index whenever a reagent lot changes, because an INR calculated on the previous lot’s index is quietly wrong.
Analyzers it runs on
Calibrator, controls and companion tests
Delivered with both control levels and the rest of the coagulation panel, on the same schedule as PT Reagent.
Storage and handling
Refrigerated, with reconstitution and on-instrument stability exactly as the insert directs.
Buying PT Reagent in the Philippines
PT Reagent is supplied for the C2000-2 / C2000-4 and C3100. We deliver it with Coagulation Control, normal and Coagulation Control, abnormal, because a run held up waiting on a separate order costs the same shift a stock-out does. Delivery is scheduled against your monthly PT Reagent count, so the bench is not rationing tests in the last week of the month. How we plan coagulation supply.
Questions about PT Reagent
Why is INR reported instead of just the clotting time in seconds?
Because the raw seconds depend on the reagent used, so the same patient would get different numbers in different laboratories. The INR calculation normalises the result against a reference using a sensitivity index specific to the reagent lot, which lets a warfarin dose be managed consistently wherever the patient is tested. Entering the correct index for each new lot is essential to that.
What happens if the sensitivity index is not updated for a new lot?
The clotting time will still be measured correctly, but the INR calculated from it will be wrong, and nothing on the analyzer will announce it. Because warfarin doses are adjusted from the INR, that error reaches the patient. Updating the index at every lot change should be a documented step rather than something remembered.
Order PT Reagent
Tell us your monthly PT Reagent volume and we will quote a supply schedule for C2000-2 / C2000-4. We reply within one business day.
Request a quotation