1911 Lupus Anticoagulant: DRVVT reflex to Confirmation

LAC Screen Result CLOT DET  < 1.21   

Specimen Requirements
1 Plasma Citrated 2 (1) mL   Frozen - 14 Day(s) See COLLECTION INSTRUCTIONS for platelet-poor plasma. 

Clinical utility
The presence of Lupus Anticoagulant can cause hypercoagulable states, as well as fetal loss. Due to its heterogeneous nature, no single assay can absolutely identify the presence of LA in every test plasma. Other LA tests should be performed if LAC Confirm is negative.

Collection Instruction
Instructions for platelet-poor plasma:
1. Draw a plain red top tube to remove tissue fluid contamination.
Discard this tube.
2. Draw blood into a buffered citrate collection tube (light blue
top) filled to the proper level. Do not overfill.
3. The blood-to-anticoagulant ratio should be 9:1; inadequate
filling of the collection device will decrease this ratio and
may lead to inaccurate results.
4. Adjust the final citrate concentration in the blood
of patients who have hematocrit values above 0.55 (55%). For
hematocrits below 20%, there are no current data to
support a recommendation for adjusting the citrate concentration.
5. The needle gauge could be between 19-22. For pediatric
patients a 21-23 gauge needle may be used.
6. Invert gently 6 times to mix. Process immediately.
7. Centrifuge for 15 min at 2500 x g.
8. Remove plasma using a plastic pipette and transfer to a new tube.
9. Repeat centrifugation at 2500 x g for 15 min to assure
complete platelet removal.
10. Dispense the plasma into 2 or more plastic tubes using a plastic
transfer pipette. Label tubes appropriately.
11. Freeze immediately. Stable for 2 months at -20 C and 6 months at
-70 C.
12. Specimen must remain frozen at all times. Ship to Specialty within
24 hours on dry ice.
13. Specimen should not be submitted if it is hemolyzed, microclots
are present, the tube is less than 90% filled or a specimen with
hematocrit >55% is collected without anticoagulant adjustment.

Reported: Same day

CPT Code: 85613

Notes: For LAC Screen (DRVVT), heparin concentrations greater than 1 U/mL can cause false-positive results: thus, heparinized plasma is not acceptable. When result for LAC Screen is >1.2, LAC Confirm will be performed for an an additional fee. Add CPT code 85613.