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Quick Cell Proliferation Colorimetric Assay Kit

based on 37 citations in multiple journalsQuick Cell Proliferation Colorimetric Assay Kit375 5
Sensitive, Non-radioactive Assay
Catalog #: K301
SKU-Size Size Price Qty
K301-500 500 assays
K301-2500 2500 assays
More Sizes Get Quote

Product Details

Detection Method Absorbance (420-480 nm)
Species Reactivity N/A
Applications This fast and sensitive cell proliferation assay uses a water-soluble tetrazolium salt WST-1.
The assay measures cell proliferation in response to growth factors/cytokines/mitogens/and nutrients etc.
Features & Benefits • Simple one-step procedure; takes less than 4 hours
• Fast and convenient
• The method is so easy that it requires no washing/harvesting/or solubilization steps and is faster and more sensitive than MTT/XTT/or MTS-based assays. The entire assay can be performed directly in a 96-well plate.
Kit Components • WST-1 Reagent (lyophilized)
• Electro Coupling Solution (ECS)
Storage Conditions -20°C
Shipping Conditions Gel Pack
USAGE For Research Use Only! Not For Use in Humans.


The Quick Cell Proliferation Assay Kit provides all reagents and detailed instructions for a fast and sensitive quantification of cell proliferation and viability. The assay is based on the cleavage of the tetrazolium salt WST-1 to formazan by cellular mitochondrial dehydrogenases. Expansion in the number of viable cells resulted in an increase in the activity of the mitochondrial dehydrogenases, which leads to the increase in the amount of formazan dye formed. The formazan dye produced by viable cells can be quantified by multi-well spectrophotometer (microtiter plate reader) by measuring the absorbance of the dye solution at 440 nm. The assay can be used for the measurement of cell proliferation in response to growth factors, cytokines, mitogens, and nutrients, etc. It can also be used for the analysis of cytotoxic compounds like anticancer drugs and many other toxic agents and pharmaceutical compounds. The new method is so simple, requiring no washing, no harvesting, and no solubilization steps, and is faster and more sensitive than MTT, XTT, or MTS-based assays. The entire assay can be performed in a microtiter plate.

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Does culture medium with phenol red interfere with the assay?
No, phenol red does not interfere with the assay.
Why using 600 nm as reference wavelength?
Cells themselves can have absorbance and the thickness of cell layer can also block light passing through. The readings of cells themselves at 450nm and 600 nm should be the same, as the absorbance is due to cells themselves, not any color development. Therefore, the readings at 600 nm due to cells themselves should be subtracted from the readings of treated and untreated samples.
During referencing, would you use absorbance at 600 or 690nm? Do you deduct the reference value from the reading at 450 nm?
You can use either 600 or 690 nm. It does not matter. But you should deduct reference value from the sample readings (e.g., 0.6-0.2) for calculations.
The blank value is very high, as high as 0.3 to 0.6. Is it normal?
This is still normal. However, if you decrease your cell number, the background value should decrease proportionally. 
How to tell the reagents not good anymore?
If the ECS solution changes from purple-red color to yellow-orange color, you should not use the kit anymore, as the results would not be reliable. Reading could be low and also background would be high.
What can I use for positive control? Why I can not see positive results from cell stimulation?
The best control is reading 10000 cells vs 100000 cells to see whether there is big difference, which will tell whether the kit working properly. Several possibilities for no stimulation effect are:
1. Too many cells, no room to proliferate any more.
2. Too little cells, no enough signal to see.
3. The cells did not response to the stimulant.
Please confirm with us whether # K301-500 needs to have Blank or not. If yes, which buffer should be used?
Yes, you have to use a blank for this assay. Have triplicate wells without cells which contain culture medium and WST-1/ECS solution as a blank.
We have a After 4 hour's incubation, there is no difference between medium and medium with cell (no drug treatment). After 8 hour's incubation, there is a slight difference. Is it normal? The incubation time is much longer than datasheet.
Please verify that the cells are in their logarithmic phase of growth the assay is being done. If the growth rate has already slowed down and the assay is done after that, it may take longer as in the current case.
Can this kit be used with samples like bacteria, plants, drosophila, yeast etc?
We have optimized the kit with mammalian samples. However, theoretically these kits should work with samples from multiple species/sources. Since the optimal conditions depend on the sample type, the protocol has to be be adapted to fit the samples for efficient results. Please refer to this kit's citations to see what kind of samples have been used with this kit other than mammalian samples.
Can we use frozen samples with this assay?
Fresh samples are always preferred over frozen samples. However, frozen samples can also be used, provided, they were frozen right after isolation, were not freeze thawed multiple time (for which we recommend aliquoting the samples before freezing) and have been frozen for relatively short periods.
What is the exact volume of sample required for this assay?
There is no specific volume we can recommend for the amount any sample to be used since it is completely sample concentration and quality based. You have to do a pilot expt with multiple sample volumes to determine the optimal volume which gives a reading within the linear range of the standard curve. Please refer to the citations for this product to see what other clients have used with similar sample types.
Do you have trial sizes of this kit?
Unfortunately, we do not have trial sizes of this kit available. However, if you are based in the US or Canada, we will give you a 10% off list price introductory discount on its purchase price. If you are based out of this area please contact yopur regional BioVision distributor.
What is the shelf life of this kit?
This kit is good for 12 months from the date of shipment in the unopened form when stored at the appropriate temperature and appropriate conditions. After opening and reconstitution, some of the components in this kit are good for 2 months at -20°C. Please refer to the datasheet for storage information and shelf life of each of the components.
Can we purchase individual components of this kit?
Yes, you can purchase any of the kit's components without the whole kit. Please refer to the component Cat #s mentioned on the datasheet for ordering.
Can we use an alternate buffer for sample preparation (cell lysis, sample dilutions etc)?
Our assay buffers are optimized for the reactions they are designed for. They not only contain some detergents for efficient lysis of your cells/tissue, but also contain some proprietary components required for the further reactions. Therefore, we highly recommend using the buffers provided in the kit for the best results.
My data shows huge variations. What could be the reason?
The rate of WST-1 cleavage may be affected by the availability of NADH, redox status of the cells and/or the presence of reactive oxygen species. If you see huge variability even after taking all the precautions it could be simply because of the cell type you are using. In that case, it is best to validate your results by using alternative techniques like LDH assay.
I see precipitates in my WST reagent. What should I do?
Incubation at 370C for 10 minutes followed by gentle agitation was always sufficient to resolve the problem
What are the potential interference?
Phenol Red will increase the absorbance by no more than 0.1 OD units; however, the negative controls make it possible to compensate for this. The addition of up to 10% FCS/FBS also causes no problems -
What are the advantages of WST-1 compared to other cell proliferation agents?
WST-1 has multiple advantages:
1. Unlike MTT, WST-1 forms water soluble formazan crystals which can be measured without solubilization.
2. WST-1 is more stable compared to XTT and MTS. Thus it can be used as a ready to use solution, stored at 4°C without significant degradation.
3. WST-1 has a wider linear range and develops color faster compared to XTT.
Can the kit work on bacteria or yeast cells?
The kit has been standardized for mammalian cells only
Hsueh, Yu-Sheng et al. (2017) Laminin-Alginate Beads as Preadipocyte Carriers to Enhance Adipogenesis In Vitro and In Vivo, Tissue Eng Part A. 2017 Mar;23(5-6):185-194.
Fang, Y. et al., (2017)  IL-33 acts as a foe to MIA PaCa-2 pancreatic cancer, Medical Oncology, Feb.2017, 34(2), 23
Cheng et al., Autophagy modulates endoplasmic reticulum stress-induced cell death in podocytes: A protective role. Experimental Biology and Medicine, Oct 2014; 10.1177/1535370214553772.
Murdoch et al., Glutaredoxin-1 Up-regulation Induces Soluble Vascular Endothelial Growth Factor Receptor 1, Attenuating Post-ischemia Limb Revascularization. J. Biol. Chem., Mar 2014; 289: 8633 - 8644.
Sefton et al., MK-2206, an AKT Inhibitor, Promotes Caspase-Independent Cell Death and Inhibits Leiomyoma Growth.Endocrinology,  Nov 2013; 154: 4046 - 4057.
For more citations of this product click here