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#15900: Activated Protein C Resistance
(APCR Protein C Resistance, Activated)
COMPONENTS
SPECIMEN REQUIREMENTS
GENERAL INFORMATION
COLLECTION INSTRUCTIONS Patient should be at rest before drawing blood. Sensitivity and specificity for FV Leiden are not affected by Coumadin. The assay allows for analysis of plasma from heparinized patients at heparin levels < or equal to 1 IU/mL, unfractionated or LMW. Presence of Antiphospholipid Antibodies can cause inaccurate APCR results. Care should be taken to avoid contact activation of samples since this may lead to activation of FV and FVIII. Instructions for platelet-poor plasma: Draw a plain red top tube to remove tissue fluid contamination. Discard this tube. Draw blood into a buffered citrate collection tube (light blue top) filled to proper level. Do not overfill. 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. Adjust the final citrate concentration in the blood of patients who have hematocrit values above 0.55 (55%). For hematocrits below 20%, there is no current data available to support a recommendation for adjusting the citrate concentration. The needle gauge could be between 19-22 (pediatric: 21-23 gauge needle). Invert gently 6 times to mix. Process immediately. Centrifuge for 15 min at 2500 x g. Remove plasma using a plastic pipette. Repeat centrifugation at 2500 x g for 15 minutes to assure complete platelet removal. Dispense the plasma into 2 or more plastic tubes using a plastic transfer pipette. Freeze immediately. Stable for 2 months at -20 C and 6 months at -70 C. Specimen must remain frozen at all times. Ship to Specialty within 24 hours on dry ice. Specimen should not be submitted if: it is hemolyzed; microclots are present; the tube is less than 90% filled; a specimen with hematocrit >55% is collected without anticoagulant adjustment. |