Cross-reactivity observed with 1 or more available related molecules.< 50% cross-species reactivity observed with species tested.
No significant interference observed with available related molecules.
The Quantikine Human CXCL4/PF4 Immunoassay is a 4.5 hour solid-phase ELISA designed to measure human PF4 in cell culture supernates, serum, and platelet-poor plasma. It contains E.
coli-expressed recombinant human PF4 and has been shown to accurately quantitate the recombinant factor. Results obtained using natural human PF4 showed linear curves that were parallel to the standard curves obtained using the Quantikine kit standards. These results indicate that this kit can be used to determine relative mass values for naturally occurring human PF4.
Intra-Assay Precision (Precision within an assay) Three samples of known concentration were tested twenty times on one plate to assess intra-assay precision.
Inter-Assay Precision (Precision between assays) Three samples of known concentration were tested in twenty separate assays to assess inter-assay precision. Assays were performed by at least three technicians using two lots of components.
The recovery of human PF4 spiked to levels throughout the range of the assay in various matrices was evaluated.
Average % Recovery
Cell Culture Media (n=4)
Platelet-poor EDTA Plasma (n=4)
To assess linearity of the assay, samples containing and/or spiked with high concentrations of human PF4 were diluted with Calibrator Diluent to produce samples with values within the dynamic range of the assay.
Preparation and Storage
Store the unopened product at 2 - 8 °C. Do not use past expiration date.
CXCL4/PF4 is a secreted chemokine that is expressed by megakaryocytes and restrains the coagulation cascade. It is released by activated platelets and regulates Thrombin/Thrombomodulin complexes, activated Protein C (APC), Coagulation Factor Xa, and Fibrin. The anticoagulant heparin neutralizes CXCL4 procoagulant effects. Complexes of heparin and CXCL4 trigger antibody formation that causes the pathological syndrome HITT. Immunogenic complexes of CXCL4 with Apolipoprotein H contribute to antiphospholipid syndrome (APS). CXCL4 interferes with the proliferative and angiogenic functions of FGF-2 and VEGF. However, it can also exert proinflammatory and pro-atherogenic effects on monocytes, macrophages, and endothelial cells. CXCL4 may signal through CXCR3B in humans.
Refer to the product for complete assay procedure.
Bring all reagents and samples to room temperature before use. It is recommended that all samples, standards, and controls be assayed in duplicate.
Prepare all reagents, standard dilutions, and samples as directed in the product insert.
Remove excess microplate strips from the plate frame, return them to the foil pouch containing the desiccant pack, and reseal.
100 µL Assay Diluent
Add 100 µL of Assay Diluent to each well.
50 µL Standard, Control, or Sample
Add 50 µL of Standard, control, or sample to each well. Cover with a plate sealer, and incubate at room temperature for 2 hours on a horizontal orbital microplate shaker.
Aspirate each well and wash, repeating the process 3 times for a total of 4 washes.
200 µL Conjugate
Add 200 µL of Conjugate to each well. Cover with a new plate sealer, and incubate at room temperature for 2 hours on the shaker.
Aspirate and wash 4 times.
200 µL Substrate Solution
Add 200 µL Substrate Solution to each well. Incubate at room temperature for 30 minutes on the benchtop. PROTECT FROM LIGHT.
50 µL Stop Solution
Add 50 µL of Stop Solution to each well. Read at 450 nm within 30 minutes. Set wavelength correction to 540 nm or 570 nm.
R&D Systems personnel manually curate a database that contains references using R&D Systems products.
The data collected includes not only links to publications in PubMed,
but also provides information about sample types, species, and experimental conditions.