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Test Code LAAPS1 LA/APS Comprehensive (Functional and Antigenic) Level 1 Package

Specimen Type

Plasma and serum

Container/Tube

4 light blue top tubes (3.2% sodium citrate) and 2 red top
tubes

Offsite Collection Instructions

Whole blood sample must arrive in the laboratory within
three hours of specimen collection.

 

If transport time exceeds three hours, follow centrifugation
instructions:

  • Samples must be centrifuged at >2500 x g for 10
    minutes at room temperature.
  • Carefully remove the plasma from the cells using a plastic
    transfer pipette avoiding the buffy coat.
  • Dispense the plasma into a plastic tube (glass is not
    acceptable) and centrifuge the plastic tube for a second
    centrifugation at >2500 x g for 10 minutes at room
    temperature.
  • Remove the top portion of the plasma being careful to leave
    a small amount of plasma at the bottom of the tube undisturbed
    (about 250mL). Then, aliquot the removed plasma into 4 plastic tubes
    containing a minimum of 1.0 mL of specimen in each tube.
  • The plasma samples must then be frozen at -20 C.
  • Once solidly frozen they must be shipped on dry ice. Frozen
    plasma samples that have thawed in transit will be rejected.

Note: For clients who do not have access to dry ice DO NOT
freeze the specimen. Follow the centrifugation instructions and
send fresh plasma or send whole blood sample. It now becomes
vital that the specimen arrives in the lab within three hours of
collection.

 

Serum specimen should be centrifuged at >2500 x g
for 10 minutes. Aliquot removed serum into 3 tubes containing
minimum of 0.5 mL of specimen each. They may be sent
refrigerated or frozen.
Note: Frozen serum samples that have thawed in transit
will be rejected.

Turnaround Time

4 days

Test Includes

The package includes both functional lupus anticoagulant
(LA) testing and antigenic testing for detection of
antiphospholipid antibodies. The package includes
functional LA testing by three independent systems one based
on a dilution of the Russell viper venom time (Dilute Russell
Viper Venom Time, or DRVVT ), one based on a dilution of the
activated partial thromboplastin time ( PTT-LA ), and
one based on a dilution of the prothrombin time
( dPT ). In each case a screening test is
performed. If results in the screen are sufficiently
prolonged, testing will proceed to a mixing study. If there is
not sufficiently strong correction of the abnormality in the
mixing phase, testing will then proceed to a confirmatory phase for
that testing system. While the actual number of seconds of clotting
times in the various phases of the specific testing systems
necessarily varies as a function of reagent lot changes, the
criterion for determination of normal vs abnormal with respect
to detection of a LA remains constant: A 99th percentile upper
limit for the normal reference population is determined for the
confirmatory phase in each testing system at the time of lot
changes, and is used as the basis for reporting of results in
EPIC.

The package also includes testing for the presence of IgG
and IgM antibodies directed against beta-2 glycoprotein I (beta-2
GPI). Because the conformational presentation of beta-2 GPI
determines whether or not a particular patient antibody will
recognize it as an antigenic target, the beta-2 GPI is employed
in two different forms. The first employs the beta-2 GPI directly
attached to solid phase, and is termed the IgG or IgM anti-
beta-2 GPI  assay. The second employs cardiolipin
directly attached to the solid phase, with beta-2 GPI then
secondarily being bound to the cardiolipin, and is termed the
IgG or IgM anti-cardiolipin  assay.

Preferred Volume

8 mL plasma in 4 aliquots, 2 mL each and 2 mL serum

UCMC Collection Instructions

Specimens for this package may be collected and sent to the
laboratory at any time

Test Usage

The package includes both functional lupus anticoagulant
(LA) testing and antigenic testing for detection of
antiphospholipid antibodies.

Hypercoagulable workup.

Additional Information

Note: Each of the three functional LA testing systems now in
use employ a heparin-neutralizing agent capable of neutralizing
levels of heparin employed therapeutically in patients.  However,
with the advent of direct thrombin inhibitors, these tests will
no longer function properly to detect possible LAs.
Accordingly, if the aPTT-LA screen is prolonged, a TT will be
performed.  If this TT is prolonged, then a TT preceded by
incubation of the plasma with heparinase will be performed to
determine if heparin might be the cause of the prolongation. In
contrast to plasma anticoagulated with unfractionated or low
molecular weight heparin, plasma anticoagulated with direct
thrombin inhibitors will not show a shortening of the TT
following heparinase incubation. Accordingly in such a situation,
further LA functional testing will not be performed.

 

All 3.2% sodium citrate light blue top tubes require a ratio
of 9 parts blood to 1 part anticoagulant (example: a 3.0 mL tube
requires 2.7 mL blood added to 0.3 mL of anticoagulant).

Fee Code

30585613, 30185732, 30085705, 30086147, 30186147,
30086146, 30186146,

Synonyms

Lupus; LA; APS; LA/APS; APS/LA; Dilute Russell Viper Venom
Screen (DRVVT); PTTLA; PTT with lupus sensitive reagent; Dilute
Prothrombin Time (DPT); Anticardiolipin Antibodies; B2GP;
Beta-2 Glycoprotein I Antibodies; LAAPS1

STAT Turnaround Time

n/a

Specimen Minimum Volume

5 mL plasma and 1 mL serum

DAY(S) AND TIME(S) PERFORMED

Functional lupus anticoagulant is performed 3 times a week
Monday- Friday 1st shift only. Antigenic testing
is performed on Mondays and Thursdays 1st shift only.

STAT DAY(S) AND TIME(S) PERFORMED

Not Available

CPT

86147, 86146, 85613, 85670, 85732, 85597, 85705

Method Name

Functional LA testing employs clotting methodology.
Antigenic testing is done by chemiluminescence method.

Reference Values

DRVVT Screen: <41.0 seconds
PTT-LA Screen: <40.6 seconds
dPT Screen: <46.9 seconds
Anticardiolipin IgG <20.1 CU
Anticardiolipin IgM <20.1 CU
Beta-2 GPI IgG <20.1 CU
Beta-2 GPI IgM <20.1 CU

Reject Due To

Specimens that have wrong ratio of blood to anticoagulant
(fill volume) clotted or grossly hemolyzed.