| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
DRVVT MIX
Message"Platelet Poor Plasma for Lupus Anticoagulant
Testing
Perhaps the most important step in the diagnosis of the
lupus anticoagulant (LA) is appropriate specimen
collection and processing. It is imperative that the
laboratory take extra precautions in preparing
platelet-poor plasma (PPP). The more platelet-free the
sample, the greater the sensitivity of most test systems
to the presence of LA. Ideally, PPP should have a
platelet count of less than 10 x 109 per liter (<10,000
/uL). Although the sample collection process described
in the Coagulation Specimens in the Specimen Collection
section of Test Directory should yield PPP, the
following double-spin technique can also be used:
1. Spin down specimen at 1500 x g for 15 minutes.
2. Transfer the plasma to a plastic tube with a plastic
Pasteur pipette, staying away from the buffy coat layer.
Spin down the plasma portion again at 1500 x g for 15
minutes. With another plastic Pasteur pipette, transfer
the plasma to another plastic tube, staying clear of the
bottom of the tube where the platelets lie.
Alternatively, the plasma may be filtered using a 0.2
micron filter.
3. Transfer plasma into a plastic tube using a plastic
Pasteur pipette. Do not use glass tubes or glass Pasteur
pipettes, as glass can activate the clotting cascade.
4. Label each tube plasma. Submit a plasma aliquot for
each and every coagulation assay requested (one tube for
each test). If possible, submit one additional plasma
aliquot for repeat and/or test additions.
Reference: NCCLS guidelines H3-A3 and H21-A2"
Testing
Perhaps the most important step in the diagnosis of the
lupus anticoagulant (LA) is appropriate specimen
collection and processing. It is imperative that the
laboratory take extra precautions in preparing
platelet-poor plasma (PPP). The more platelet-free the
sample, the greater the sensitivity of most test systems
to the presence of LA. Ideally, PPP should have a
platelet count of less than 10 x 109 per liter (<10,000
/uL). Although the sample collection process described
in the Coagulation Specimens in the Specimen Collection
section of Test Directory should yield PPP, the
following double-spin technique can also be used:
1. Spin down specimen at 1500 x g for 15 minutes.
2. Transfer the plasma to a plastic tube with a plastic
Pasteur pipette, staying away from the buffy coat layer.
Spin down the plasma portion again at 1500 x g for 15
minutes. With another plastic Pasteur pipette, transfer
the plasma to another plastic tube, staying clear of the
bottom of the tube where the platelets lie.
Alternatively, the plasma may be filtered using a 0.2
micron filter.
3. Transfer plasma into a plastic tube using a plastic
Pasteur pipette. Do not use glass tubes or glass Pasteur
pipettes, as glass can activate the clotting cascade.
4. Label each tube plasma. Submit a plasma aliquot for
each and every coagulation assay requested (one tube for
each test). If possible, submit one additional plasma
aliquot for repeat and/or test additions.
Reference: NCCLS guidelines H3-A3 and H21-A2"
Test Code
117912
Alias/See Also
Dilute Russell Viper Venom
CPT Codes
85613
Includes
"If dRVVT Screen is prolonged (>45 seconds), dRVVT Confirm will be performed at an additional charge (CPT code(s): 85597).
"
"
Preferred Specimen
2.0 mL Plasma
Minimum Volume
1.0 mL
Instructions
"Please submit a separate, frozen vial for
each special coagulation assay ordered.
If the dRVVT Screen is prolonged (> 45 seconds), the
dRVVT Confirmation will be performed at an additional
charge (CPT: 85598).
If the dRVVT Confirm is positive, a dRVVT 1:1 dilution
will be performed at an additional charge (CPT: 85613)."
each special coagulation assay ordered.
If the dRVVT Screen is prolonged (> 45 seconds), the
dRVVT Confirmation will be performed at an additional
charge (CPT: 85598).
If the dRVVT Confirm is positive, a dRVVT 1:1 dilution
will be performed at an additional charge (CPT: 85613)."
Transport Container
Light Blue 3.2% Sodium Citrate
Transport Temperature
Frozen
Specimen Stability
"Room Temperature: unacceptable
Refrigerated: unacceptable
Frozen: 90 days"
Refrigerated: unacceptable
Frozen: 90 days"
Methodology
Clot Detection
Setup Schedule
Monday-Saturday Night
Report Available
Next Day
Reference Range
"
dRVVT Screen---=45 seconds
dRVVT Confirm---Negative
dRVVT 1:1 Mix---Corrected
"
dRVVT Screen---=45 seconds
dRVVT Confirm---Negative
dRVVT 1:1 Mix---Corrected
"
Clinical Significance
"Diagnosis of a lupus anticoagulant (LA) requires testing
with a least 2 screening reagents, followed by
confirmatory testing. The dRVVT screen, confirm, and mix
satisfy international guidelines for LA evaluations"
with a least 2 screening reagents, followed by
confirmatory testing. The dRVVT screen, confirm, and mix
satisfy international guidelines for LA evaluations"
