Test Details
Methodology
See individual tests.
Result Turnaround Time
Within 1 day
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Use
This test is used for initial laboratory assessment of drug, herbal and dietary supplement-induced liver injury.
Limitations
The PT test may not be sensitive to slight deficiencies of single factors. Heparin can extend the PT. Lupus anticoagulants may affect prothrombin time producing results that do not accurately reflect the true level of anticoagulation. The PT (and aPTT) results can be extended in patients receiving antithrombin anticoagulants such as hirudin and argatroban. These patients can be monitored for warfarin effectiveness with a chromogenic factor X assay, which is not affected by lupus anticoagulant or thrombin inhibitors.
Custom Additional Information
Clinically significant biochemical evidence of drug-induced liver injury (DILI) is typically defined as meeting one of the following criteria:
• Serum AST or ALT >5x Upper Limit of Normal (ULN), or ALP > 2x ULN (or pretreatment baseline is abnormal) on two occasions;
• Total serum bilirubin >2.5mg/dL along with elevated AST, ALT, or ALP level; or
• INR >1.5 with elevated AST, ALT, or ALP.
These patterns can be more precisely and quantitatively expressed though the R value at presentation when:
• R value ≥ 5.0 identifies hepatocellular liver injury
• R value 2.1- 4.9 identifies mixed liver injury
• R value ≤ 2.0 identifies cholestatic liver injury
When liver injury falls into hepatocellular or mixed categories, it may be important to exclude other causes of liver injury.1
Specimen Requirements
Specimen
Serum (preferred) or plasma and whole blood or plasma
Volume
Serum or plasma: 1 mL
PT with INR blood: 2.7 mL size tube filled to 90% capacity or 1.8 mL size tube
Minimum Volume
Serum or plasma: 0.7 mL (Note: This volume does not allow for repeat testing.)
PT with INR: 90% of full draw
Container
Red-top tube, gel-barrier tube or green-top (lithium heparin) tube; do not use oxalate, EDTA or citrate plasma and blue-top (sodium citrate) tube; do not open tube unless plasma is to be frozen.
Collection Instructions
Serum or plasma: Separate serum or plasma from cells within 45 minutes of collection.
PT with INR blood: Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate. Evacuated collection tubes must be filled to completion to ensure a proper blood-to-anticoagulant ratio. The sample should be mixed immediately by gentle inversion at least six times to ensure adequate mixing of the anticoagulant with the blood. A discard tube is not required prior to collection of coagulation samples unless the sample is collected using a winged (butterfly) collection system. With a winged blood collection set a discard tube should be drawn first to account for the dead space of the tubing and prevent under-filling of the evacuated tube. When noncitrate tubes are collected for other tests, collect sterile and nonadditive (red-top) tubes prior to citrate (blue-top) tubes. Any tube containing an alternative anticoagulant should be collected after the blue-top tube. Gel-barrier tubes and serum tubes with clot initiators should also be collected after the citrate tubes.
Print and use the Volume Guide for Coagulation Testing to ensure proper draw volume.
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | Serum or plasma: 7 days; PT with INR blood: 24 hours |
Refrigerated | Serum or plasma: 14 days |
Storage Instructions
Serum or plasma: Maintain specimen at room temperature.
PT with INR (blood): Specimens are stable at room temperature for 24 hours. If testing cannot be completed within 24 hours specimen should be centrifuged for at least 10 minutes at 1500xg: plasma should then be transferred to a Labcorp PP transpak frozen purple tube with screw cap (Labcorp No 49482). Freeze immediately and maintain frozen until tested.
Causes for Rejection
Serum or plasma: Gross hemolysis; excessive lipemia; improper labeling
PT with INR blood: Clotted specimen; hemolysis; tube <90% full; improper labeling; specimen collected in tube other than 3.2% citrate; refrigerated specimen
Footnotes
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 010045 | DILI Profile | 001099 | Bilirubin, Total | mg/dL | 1975-2 | |
| 010045 | DILI Profile | 001107 | Alkaline Phosphatase | IU/L | 6768-6 | |
| 010045 | DILI Profile | 001123 | AST (SGOT) | IU/L | 1920-8 | |
| 010045 | DILI Profile | 001545 | ALT (SGPT) | IU/L | 1742-6 | |
| 010045 | DILI Profile | 115107 | INR | 6301-6 | ||
| 010045 | DILI Profile | 015289 | Prothrombin Time | sec | 5902-2 | |
| 010045 | DILI Profile | 010037 | DILI R Value | 22032-7 | ||
| Order Code | 010045 | |||||
| Order Code Name | DILI Profile | |||||
| Order Loinc | ||||||
| Result Code | 001099 | |||||
| Result Code Name | Bilirubin, Total | |||||
| UofM | mg/dL | |||||
| Result LOINC | 1975-2 | |||||
| Order Code | 010045 | |||||
| Order Code Name | DILI Profile | |||||
| Order Loinc | ||||||
| Result Code | 001107 | |||||
| Result Code Name | Alkaline Phosphatase | |||||
| UofM | IU/L | |||||
| Result LOINC | 6768-6 | |||||
| Order Code | 010045 | |||||
| Order Code Name | DILI Profile | |||||
| Order Loinc | ||||||
| Result Code | 001123 | |||||
| Result Code Name | AST (SGOT) | |||||
| UofM | IU/L | |||||
| Result LOINC | 1920-8 | |||||
| Order Code | 010045 | |||||
| Order Code Name | DILI Profile | |||||
| Order Loinc | ||||||
| Result Code | 001545 | |||||
| Result Code Name | ALT (SGPT) | |||||
| UofM | IU/L | |||||
| Result LOINC | 1742-6 | |||||
| Order Code | 010045 | |||||
| Order Code Name | DILI Profile | |||||
| Order Loinc | ||||||
| Result Code | 115107 | |||||
| Result Code Name | INR | |||||
| UofM | ||||||
| Result LOINC | 6301-6 | |||||
| Order Code | 010045 | |||||
| Order Code Name | DILI Profile | |||||
| Order Loinc | ||||||
| Result Code | 015289 | |||||
| Result Code Name | Prothrombin Time | |||||
| UofM | sec | |||||
| Result LOINC | 5902-2 | |||||
| Order Code | 010045 | |||||
| Order Code Name | DILI Profile | |||||
| Order Loinc | ||||||
| Result Code | 010037 | |||||
| Result Code Name | DILI R Value | |||||
| UofM | ||||||
| Result LOINC | 22032-7 |
| Order Code | Order Name | Result Code | Result Name | UofM | Result LOINC | |
|---|---|---|---|---|---|---|
| Reflex 1 | 115109 | INR (Thromborel-S) | 115109 | INR (Thromborel-S) | 6301-6 | |
| Reflex 1 | ||||||
| Order Code | 115109 | |||||
| Order Name | INR (Thromborel-S) | |||||
| Result Code | 115109 | |||||
| Result Name | INR (Thromborel-S) | |||||
| UofM | ||||||
| Result LOINC | 6301-6 | |||||
| Order Code | Order Name | Result Code | Result Name | UofM | Result LOINC | |
|---|---|---|---|---|---|---|
| Reflex 1 | 015290 | PT (Thromborel-S) | 015290 | PT (Thromborel-S) | sec | 5902-2 |
| Reflex 1 | ||||||
| Order Code | 015290 | |||||
| Order Name | PT (Thromborel-S) | |||||
| Result Code | 015290 | |||||
| Result Name | PT (Thromborel-S) | |||||
| UofM | sec | |||||
| Result LOINC | 5902-2 | |||||