Clinical Pathology Laboratory - Coagulation Protocols
Collection protocol Frequently asked questions Instruments: STA Compact; Diagnostica Stago, Parsippany, NJ
FDP Plasma Kit; Diagnostica Stago, Parsippany, NJ Sample Requirements: Citrated plasma (light blue top tube); tubes of appropriate size should be selected to ensure an optimal ratio of citrate to whole blood. Required volumes are listed in the table below. Tubes should be centrifuged at 2500 rcf* for 10 minutes, citrated plasma removed with a plastic pipet tip and placed into a sterile, non-citrated, plastic tube within 2 hours of collection. Samples must not come into contact with glass. Samples will be run the same day, and samples >24 hours old will be rejected. Please contact the lab for further instruction if you would like to submit archived, frozen samples for analysis.
(*RCF = relative centrifugal force = 0.00001118 x r (rotational radius in cm) x RPM2) Tests Available: Coagulation tests
| Option | Description of item | Required serum volume
(Note: not whole blood volume) | | 1 | Prothrombin Time (PT) | 250 μLs** | | 2 | Activated Partial Thromboplastin Time (aPTT) | 250 μLs** | | 3 | PT and aPTT | 500 μLs** | | 4 | Fibrin Degradation Products (FDPs) | 150 μLs** | | 5 | Coagulation Profile (PT, APTT, FDPs, fibrinogen and platelet count) | 650 μLs- citrated plasma
500 μLs- EDTA anticoagulated whole blood
(see CBC) | **If the specimen is short volume, the lab will attempt to run as many tests as possible. Appropriate Tubes: The following tubes are suitable for blood collection and analysis using the STA Compact and FDP Plasma Kit. Please contact the lab if you have questions regarding the appropriate tube to utilize for your samples. | Name | Sample volume | Mfr # | | BD Vacutainer Blood Tubes with 3.2% sodium citrate | 1.8 mL | 363080 | | BD Vacutainer Blood Tubes with 3.2% sodium citrate | 2.7 mL | 363083 | Sample Handling: Following collection, tubes should be inverted 8 times to ensure adequate mixing of blood and sodium citrate. Label tubes using permanent marker with a legible, simplified numbering system. Samples should be refrigerated as soon as possible following collection. They should not be frozen or transported directly on ice. Transport with cold packs is recommended. Results: Results are available in Excel format. Common Interferences: Complete filling of the tube is important to ensure the appropriate ratio of citrate to whole blood (1:9 or 3.2% citrate). Over-citrated plasma (under-filled tube) may result in prolonged clotting times. Under-citrated plasma (over-filled tube) may result in shortened clotting times.
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