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Description
Human CD34 ELISA KitProduct Specification Usage Required experimental equipment: 1. Microplate reader (450nm) 2. High precision pipettes and pipette tips: 0. 5 10uL, 5 50uL, 20 200uL, 200 1000uL 3. 37C incubator 4. Distilled or deionized water Sample preparation and requirements: Tissue homogenization: Rinse the tissue with pre chilled PBS (0. 01M, pH 7. 4) to remove residual blood (lysed red blood cells in the homogenate will affect the measurement results). Weigh and
Product Specification
| Usage | Required experimental equipment: 1. Microplate reader (450nm) 2. High-precision pipettes and pipette tips: 0.5-10uL, 5-50uL, 20-200uL, 200-1000uL 3. 37°C incubator 4. Distilled or deionized water Sample preparation and requirements: Tissue homogenization: Rinse the tissue with pre-chilled PBS (0.01M, pH 7.4) to remove residual blood (lysed red blood cells in the homogenate will affect the measurement results). Weigh and mince the tissue. Add the minced tissue to the appropriate volume of PBS (generally a 1:9 weight-to-volume ratio, e.g., 1g of tissue sample to 9mL of PBS. The specific volume can be adjusted according to experimental needs and recorded. It is recommended to add protease inhibitors to the PBS) in a glass homogenizer and grind thoroughly on ice. To further lyse tissue cells, the homogenate can be sonicated or repeatedly frozen and thawed. Finally, centrifuge the homogenate at 5000×g for 5-10 minutes, and collect the supernatant for analysis. Cell Lysis Buffer: Adherent cells should be gently washed with pre-chilled PBS, then trypsinized and harvested by centrifugation at 1000×g for 5 minutes. Suspension cells can be harvested directly by centrifugation. Collected cells should be washed three times with pre-chilled PBS and resuspended in 150-200 μL of PBS per 1×10^6 cells (it is recommended to add protease inhibitors to the PBS; if the cell count is very low, reduce the PBS volume appropriately). Disrupt the cells by repeated freezing and thawing or sonication. Centrifuge the extract at 1500×g for 10 minutes at 2-8°C, and collect the supernatant for analysis. Other biological fluids: Centrifuge at 1000xg for 20 minutes, remove the supernatant, and test. Pre-test preparation: 1. Remove the test kit from the refrigerator 10 minutes in advance and equilibrate to room temperature. 2. Prepare the standard gradient working solution: Add 1 mL of universal diluent to the lyophilized standard, let it stand for 15 minutes to completely dissolve, then gently mix (concentration is 20 ng/mL). Then dilute to the following concentrations: 20 ng/mL, 10 ng/mL, 5 ng/mL, 2.5 ng/mL, 1.25 ng/mL, 0.625 ng/mL, 0.3125 ng/mL, and 0 ng/mL. Serial dilution method: Take 7 EP tubes and add 500 μL of universal diluent to each tube. Pipette 500 μL of the 20 ng/mL standard working solution into the first EP tube and mix thoroughly to make a 10 ng/mL standard working solution. Repeat this procedure for subsequent tubes. The last tube serves directly as a blank well; there is no need to aspirate the liquid from the penultimate tube. See the figure below for details. 3. Preparation of Biotinylated Antibody Working Solution: 15 minutes before use, centrifuge the concentrated biotinylated antibody at 1000×g for 1 minute. Dilute the 100× concentrated biotinylated antibody to a 1× working concentration using universal diluent (e.g., 10µL concentrate + 990µL universal diluent). Prepare immediately before use. 4. Prepare the enzyme conjugate working solution: 15 minutes before use, centrifuge the 100× concentrated enzyme conjugate at 1000×g for 1 minute. Dilute the 100× concentrated HRP enzyme conjugate to a 1× working concentration with universal diluent (e.g., 10 μL of concentrate + 990 μL of universal diluent). Prepare immediately. 5. Prepare the 1× wash solution: Dispense 10 mL of 20× wash solution into 190 mL of distilled water (concentrated wash solution removed from the refrigerator may crystallize; this is normal. Allow to stand at room temperature until the crystals have completely dissolved before preparing). Procedure: 1. Remove the desired strips from the aluminum foil bag after equilibration at room temperature for 10 minutes. Seal the remaining strips in a ziplock bag and return to 4°C. 2. Sample addition: Add 100 μL of sample or standard of varying concentrations to the corresponding wells. Add 100 μL of universal diluent to the blank wells. Cover with a film and incubate at 37°C for 60 minutes. (Recommendation: Dilute the sample to be tested at least 1-fold with universal diluent before adding it to the ELISA plate. This will reduce the impact of matrix effects on the test results. The sample concentration should be multiplied by the corresponding dilution factor when calculating the final sample concentration. It is recommended to run replicates for all test samples and standards.) 3. Add Biotinylated Antibody: Remove the ELISA plate and discard the liquid without washing. Add 100 μL of Biotinylated Antibody Working Solution directly to each well. Cover with a film and incubate at 37°C for 60 minutes. 4. Wash: Discard the liquid and add 300 μL of 1x Wash Solution to each well. Let stand for 1 minute, shake off the wash solution, and pat dry on absorbent paper. Repeat this process three times (a plate washer can also be used). 5. Add Enzyme Conjugate Working Solution: Add 100 μL of Enzyme Conjugate Working Solution to each well. Cover with a film and incubate at 37°C for 30 minutes. 6. Washing: Discard the liquid and wash the plate five times as in step 4. 7. Adding substrate: Add 90 μL of substrate (TMB) to each well, cover with a sealing film, and incubate at 37°C in the dark for 15 minutes. 8. Adding stop solution: Remove the ELISA plate and add 50 μL of stop solution directly to each well. Immediately measure the OD value of each well at a wavelength of 450 nm. Calculating experimental results: 1. Calculate the average OD value of the standard and sample replicates and subtract the OD value of the blank well as a correction factor. Plot the standard curve of the four-parameter logistic function on double-logarithmic graph paper, with concentration as the horizontal axis and OD value as the vertical axis. 2. If the sample OD value is higher than the upper limit of the standard curve, dilute the sample appropriately and retest. Multiply the sample concentration by the corresponding dilution factor. |
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| Theory | This kit uses a double-antibody sandwich enzyme-linked immunosorbent assay (ELISA). Sample, standard, biotin-labeled detection antibody, and HRP conjugate are sequentially added to microwells pre-coated with a Cluster of Differentiation 34 (CD34) capture antibody. After incubation and washing, the sample is developed using the substrate TMB. TMB converts to blue under the catalysis of HRP and to yellow under the action of acid. The intensity of the color is positively correlated with the amount of Cluster of Differentiation 34 (CD34) in the sample. The absorbance (OD) is measured at 450 nm using a microplate reader to calculate the sample concentration. | |||||||||||||||||||||||||||||||||
| Source | Human | |||||||||||||||||||||||||||||||||
| Synonym | Human Cluster Of Differentiation 34 ELISA Kit | |||||||||||||||||||||||||||||||||
| Detection Type | Double antibody sandwich method | |||||||||||||||||||||||||||||||||
| Composition |
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| Background | The CD34 molecule (CD34) is a transmembrane phospholipid protein encoded by the CD34 gene. CD34 is named after the cluster of differentiation protocol for recognizing cell surface antigens. It was first independently described on hematopoietic stem cells by Civin et al. and Tindle et al. as a cell surface glycoprotein that functions as a cell-cell adhesion factor. It may also mediate the attachment of hematopoietic stem cells to the extracellular matrix of the bone marrow or directly to stromal cells. Clinically, it is relevant to the selection and enrichment of hematopoietic stem cells for bone marrow transplantation. Due to these historical and clinical associations, CD34 expression is almost ubiquitously associated with hematopoietic cells; however, it is also present on many other cell types. | |||||||||||||||||||||||||||||||||
| General Notes | 1. Strictly adhere to the specified incubation time and temperature to ensure accurate results. All reagents must be at room temperature (20-25°C) before use. Refrigerate reagents immediately after use. 2. Improper plate washing may result in inaccurate results. Ensure that all liquid in the wells is aspirated thoroughly before adding substrate. Do not allow the wells to dry out during incubation. 3. Remove any residual liquid and fingerprints from the bottom of the plate, as this will affect the OD value. 4. The substrate developer solution should be colorless or very light in color. Do not use substrate solution that has turned blue. 5. Avoid cross-contamination of reagents and specimens to prevent erroneous results. 6. Avoid direct exposure to strong light during storage and incubation. 7. Do not expose any reagents to bleaching solvents or the strong fumes emitted by bleaching solvents. Any bleaching agent will destroy the biological activity of the reagents in the kit. 8. Do not use expired products, and do not mix components with different product numbers and batches. 9. Recombinant proteins from sources other than the kit may not be compatible with the antibodies in this kit and will not be recognized. 10. If there is a possibility of disease transmission, all samples should be managed properly and samples and testing devices should be handled according to prescribed procedures. |
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| Storage Temp. | If the unopened kit is stored at 4°C, the shelf life is 6 months. | |||||||||||||||||||||||||||||||||
| Test Range | 0.312-20 ng/mL | |||||||||||||||||||||||||||||||||
| Applications | Tissue homogenates, cell lysates, and other biological fluids |
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4.9 ★★★★★
Based on 1848 reviews
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Product Reviews
★★★★★ 5
Tough Dog Balls. Bright Orange/holes for treats
Color: B) 3" 2-Pack (Bacon)
I used to buy Starmark. But their balls got smaller and tore more easily. The color was green. I couldn’t find it when it was dropped in the grass!! Soooooo, I took a chance on this cuz it had holes in it and was bright orange. It is not scented at all or its bacon scent faded. The ball is for strong chewers. I’m a petsitter and I needed tough balls for my clients dog. Shipped quickly. Good price. Exactly as described
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Reviewed in the United States on August 16, 2025
★★★★★ 4
Worthy chew and fetch ball.
Color: L) 3" 2-Pack (Chicken)
Durable and dog loved to gnaw on it. Bright yellow color easy to keep track of for both dog and parent!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on February 16, 2026
★★★★★ 5
Flavored Dog Rubber Balls
Color: H) 2.5" 3-Pack (Beef), Color: H) 2.5" 3-Pack (Beef)
My dog absolutely loves these balls, I have a few more I had already bought, but she has an addiction to them so I had to buy more. I am able to squeeze these really easily so when she does pick them up after I’ve thrown them they’re very easy for her to pick up. They have a good thickness to them so it’s not too flimsy. It’s pretty tough and they bounce pretty high which I like and so does she know she is an aggressive chewer, but I haven’t had an issue yet with her chewing right through these, which is why I like them and we both love the fact that it smells like beef I could practically smell them through the bag, but I have a really high pitched sense of smell, and I knew she was going to love them. Not to mention you can’t beat the price.
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Reviewed in the United States on November 14, 2025
★★★★★ 5
Love These Balls
Color: H) 2.5" 3-Pack (Beef), Color: H) 2.5" 3-Pack (Beef)
These are great balls. My Border Collie can destroy a tennis ball in a couple of hours and the Kong brand ball is heavier than I like to play with in the house. These balls hold up to her biting and chewing but are lite weight and softer for bouncing off the walls.
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Reviewed in the United States on May 7, 2026
★★★★★ 3
Seems durable - but the scent is not the best
Color: B) 3" 2-Pack (Bacon)
I don't know if I'd call the scent of this "bacon," more like rubber with a hint of bacon. It's very strong. I gave my dog one of the balls & put one in a cabinet where I keep his treats & a few other unrelated odds & ends. I now hold my breath when I open that cabinet b/c good lord, the smell. I'm tempted to just give that one to the dog too, just because it'll air out eventually & then everything else in that cabinet won't smell bad.
My dog feels so-so about it. He'll briefly chase after it & chew on it, but loses interest in it pretty fast. My rather hyperactive cat also plays with it from time to time, as he seems to have more interest in most dog toys than the dog these days, so there's that. (Then again, he thinks a wide variety of random items around the house are loads of fun to toss about, so it's possible his opinion is to be taken with a grain of salt. Between the brief periods of one of these balls being chewed on & clawed at, it's stayed completely intact. I think if you have a dog who simply likes to play fetch or chew on rubber balls in general, this one would stand up to the task. But if you're expecting it to be greeted with the enthusiasm as a bacon grease covered ball might be - I'd adjust your expectations.
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Reviewed in the United States on February 19, 2023