• Assay Type
    Solid Phase Sandwich ELISA
  • Format
    96-well strip plate
  • Assay Length
    5.5 hours
  • Sample Type & Volume Required Per Well
    Cell Culture Supernates (50 uL), Serum (50 uL), EDTA Plasma (50 uL), Heparin Plasma (50 uL)
  • Sensitivity
    0.37 ng/mL
  • Assay Range
    0.6 - 40 ng/mL (Cell Culture Supernates, Serum, EDTA Plasma, Heparin Plasma)
  • Specificity
    Natural and recombinant human SP-D
  • Cross-reactivity
    < 0.5% cross-reactivity observed with available related molecules.Cross-species reactivity not tested.
  • Interference
    No significant interference observed with available related molecules.
Product Summary
The Quantikine Human SP-D Immunoassay is a 5.5 hour solid-phase ELISA designed to measure human SP-D in cell culture supernates, serum, and plasma. It contains NS0-expressed recombinant human SP-D and has been shown to accurately quantitate the recombinant factor. Results obtained using natural human SP-D 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 ocurring SP-D.

Intra-Assay Precision (Precision within an assay) Three samples of known concentration were tested on one plate to assess intra-assay precision.
Inter-Assay Precision (Precision between assays) Three samples of known concentration were tested in separate assays to assess inter-assay precision.
Serum, EDTA Plasma, Heparin Plasma
Intra-Assay Precision Inter-Assay Precision
Standard Deviation0.3710.9211.630.6171.142.5

Cell Culture Supernates
Intra-Assay Precision Inter-Assay Precision
Standard Deviation0.4950.5881.460.4950.9991.78


The recovery of SP-D spiked to levels throughout the range of the assay in various matrices was evaluated.

Sample Type Average % Recovery Range %
Cell Culture Media (n=4) 102 95-109
EDTA Plasma (n=4) 110 99-120
Heparin Plasma (n=4) 104 85-118
Serum (n=4) 106 89-118
To assess the linearity of the assay, samples containing and/or spiked with high concentrations of SP-D were serially diluted with the appropriate Calibrator Diluent to produce samples with values within the dynamic range of the assay.
Human SP-D Quantikine ELISA Kit
Preparation and Storage
  • Storage
    Store the unopened product at 2 - 8 °C. Do not use past expiration date.
Background: SP-D
Surfactant Protein D (SP-D) is a collectin family protein consisting of a collagen-like sequence followed by a C-type lectin domain. It is synthesized primarily in the lung by alveolar type II cells and unciliated bronchial epithelial cells. In addition, SP-D is produced by epithelial cells of the gastrointestinal tract and exocrine glands. SP-D binds to patterns of neutral sugars on micro-organisms to mediate direct opsonization and phagocytosis and is an important component of the innate immune system.
    • Long Name
      Surfactant Pulmonary Associated Protein D
    • Entrez Gene IDs
      6441 (Human); 20390 (Mouse);
    • Alternate Names
      COLEC7collectin-7; Collectin 7; Collectin-7; Lung surfactant protein D; PSPD; PSP-D; SFTP4; SFTP4pulmonary surfactant-associated protein D; SFTPD; SPD; SP-Dpulmonary surfactant apoprotein; surfactant protein D; surfactant, pulmonary-associated protein D; surfactant-associated protein, pulmonary 4;
    Related Research Areas
    Assay Procedure
    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.
    1.   Prepare all reagents, standard dilutions, and samples as directed in the product insert.
    2.   Remove excess microplate strips from the plate frame, return them to the foil pouch containing the desiccant pack, and reseal.

    3. 100 µL Assay Diluent
    4.   Add 100 µL of Assay Diluent to each well.

    5. 50 µL Standard, Control, or Sample
    6.   Add 50 µL of Standard, control, or sample to each well. Cover with a plate sealer, and incubate at room temperature for 3 hours.
    7.   Aspirate each well and wash, repeating the process 3 times for a total of 4 washes.

    8. 200 µL Conjugate
    9.   Add 200 µL of Conjugate to each well. Cover with a new plate sealer, and incubate at room temperature for 2 hours.
    10.   Aspirate and wash 4 times.

    11. 200 µL Substrate Solution
    12.   Add 200 µL Substrate Solution to each well. Incubate at room temperature for 30 minutes. PROTECT FROM LIGHT.

    13. 50 µL Stop Solution
    14.   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.

    Showing Results 1 - 3 of 3
    Filter your results:

    Sample Type
    1. Circulating thymus and activation-regulated chemokine/CC chemokine ligand 17 is a strong candidate diagnostic marker for interstitial lung disease in patients with malignant tumors: a result from a pilot study.
      Authors: Yamane H, Ochi N, Yamagishi T, Honda Y, Takeyama M, Takigawa N
      Ther Clin Risk Manag, 2015;11(0):949-59.
      Species: Human
      Sample Type: Serum
    2. Intraoperative cell salvage during cardiac surgery is associated with reduced postoperative lung injury.
      Authors: Engels G, van Klarenbosch J, Gu Y, van Oeveren W, de Vries A
      Interact Cardiovasc Thorac Surg, 2015;22(3):298-304.
      Species: Human
      Sample Type: Plasma
    3. Nintedanib modulates surfactant protein-D expression in A549 human lung epithelial cells via the c-Jun N-terminal kinase-activator protein-1 pathway.
      Authors: Kamio K, Usuki J, Azuma A, Matsuda K, Ishii T, Inomata M, Hayashi H, Kokuho N, Fujita K, Saito Y, Miya T, Gemma A
      Pulm Pharmacol Ther, 0;32(0):29-36.
      Species: Human
      Sample Type: Cell Lysate
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