SomaLogic CVD Secondary Risk Panel

This panel can be used for cardiovascular disease (CVD) risk assessment through the generation of a CVD risk score for the occurrence of a secondary cardiovascular event. CVD Risk Scores are calculated from the protein measurements in the SomaLogic® CVD Secondary Risk Panel. The CVD Risk Scores indicate the cumulative probability of having a cardiovascular event over time. The Risk Category compares your scores with the reference population that was studied in clinical trials. An elevated Risk Category suggests that more intensive therapy may be indicated to help reduce your risk. A lower Risk Category DOES NOT imply that treatment is not needed.

Ordering Information

SomaLogic CVD Secondary Risk Panel Composition

The SOMAmer reagents in this panel target the following seven proteins (biomarkers):

MMP-12 ANGPT2 GDF11 MSTN C7
CCL18 SERPINA3 SERPINF2

Sample Requirements

  • Only EDTA plasma from a lavender-top tube is acceptable for this test.
  • A minimum of 150uL is required.

Sample Processing Requirements

Blood sample collection protocol

  1. Check the expiration date on all of the tubes.
  2. Perform the venipuncture per institutional guidelines.
  3. Completely fill lavender-top (EDTA) tubes with the proper amount of blood for the size of tube used.
  4. Immediately invert the tubes 8-10 times and place upright in a rack.

General blood sample processing requirements

The proper processing of the collected samples is critical. Samples should be processed and frozen at -80° C within two hours of collection.

Plasma processing

  1. After collection, centrifuge collection tubes at 2200 x g (not RPM) for 15 minutes. Observe separation of blood cells and plasma, with plasma layer on top.
  2. Draw off only the plasma and immediately aliquot into appropriately labeled tubes.
  3. Place aliquoted samples in a -80°C freezer.

Storage instructions

Samples should remain frozen (-80°C) at all times.

Shipping instructions

Ship samples for overnight delivery on dry ice with a copy of the Test Requisition Form (available upon request) in the packaging. Follow all US Department of Transportation and institutional requirements for labeling, packaging and shipping of clinical specimens on dry ice.

Sample rejection/limitations

The Test Requisition Form must be complete and match the samples being shipped and submitted for testing. Samples will be rejected if they arrive in one or more of the following conditions:

  • Test Requisition Form is incomplete or incorrectly filled out
  • Sample containers are incorrectly labeled when compared to the Test Requisition Form
  • Sample leaked in transit
  • Samples were received in a condition not suitable for testing (i.e. thawed)
  • Sample were received in original blood collection tubes
  • Samples exhibit significant hemolysis based on visual observation of a dark red color in the sample
  • Insufficient volume (minimum volume is 150uL)

Test methodology

The CVD Secondary Risk Panel is based on the use of proprietary SOMAmer® reagents and performed using the SOMAscan® platform. SOMAmer reagents measure the availability of epitopes on a protein. When tested on the SOMAscan assay, a signal change can be either a change in the amount/concentration of the protein or an alteration of the protein itself that leads to differential binding of the SOMAmer reagent without change in the concentration.

In the first step of the assay, the SOMAmer reagents, which are pre-immobilized onto streptavidin beads, bind to proteins in human plasma and form cognate protein-SOMAmer complexes. The streptavidin beads are washed to remove all non-specifically associated proteins and other matrix constituents. The proteins that remain bound to the SOMAmer reagents are tagged using an NHS-biotin reagent. After the labeling reaction, the streptavidin beads are exposed to an anionic competitor solution, via a photo-cleavage reagent and as non-specific binding dissociates, the anionic competitor prevents non-specific interactions from reforming. The SOMAmer-protein complexes are released into solution by photo-cleaving the linker using ultraviolet light. The biotinylated proteins are then bound to a second streptavidin bead. Beads are washed to remove unbound SOMAmer reagents, followed by bound cognate protein-SOMAmer reagents being dissociated from their protein targets. After dissociation, the eluted SOMAmer reagents are recovered and quantified through hybridization onto DNA microarrays, detected with the Agilent Microarray scanner. The amount of SOMAmer reagent detected in hybridization reactions is proportional to epitope availability in the plasma sample. The raw signals obtained from the microarray feature extraction, in units referred to as Relative Fluorescence Units (RFU), are further processed to produce the final RFU values for CVD secondary risk assessment. These RFU values are used in conjunction with an algorithm, to compute the CVD risk score for occurrence of a secondary cardiovascular event over time.