Free Prostate Specific Antigen (Free PSA) ELISA Kit

  • Created on the 11 May, 2017.


Prostate specific antigen (PSA) is also referred to as kallikrein-3 (KLK3) or gamma-seminoprotein, it is a tissue specific protein that is not solely tumor specific. It is commonly used as one of the most important markers for prostate carcinoma, where it is displaying higher specificity when compared to other biochemical markers that are used for this application (such as carcinoembryonic antigen, PAP and total alkaline phosphatase). In recent time the measurement of serum PSA levels is becoming the general accepted method in order to improve the diagnostic specificity of digital rectal examination

PSA is an enzyme which has the ability to bind to proteins in the semen and also to break them down, this process results in the semen becoming more liquid. This can also help the sperm move more easily through the women’s fallopian tube during reproduction. Some PSA is able to pass into the bloodstream via the rich blood supply of the prostate. Essentially there are three major forms of PSA that can be distinguished, however, only two are immune reactive. The predominant form is the PSA which is a complex with α1-antichymotrypsin a small amount which is not protein bound and is known as free PSA. The inactive free PSA (f-PSA) only represents about 10 – 40% of the immunologically detectable PSA. The analysis of free serum PSA in conjunction with total PSA, is found to improve specificity of prostate cancer screening in men that display elevated levels total serum PSA.


Human free PSA ELISA kit is designed for detecting in vitro quantitative concentrations of free prostate specific antigen (gamma-seminoprotein, kallikrein-3) in human plasma and serum. This assay has a minimum sensitivity limit of 0.1 ng/ml.


The minimum detection sensitivity level of human free PSA (kallikrein-3, gamma-seminoprotein) using this human free prostate-specific antigen ELISA kit was 0.1 ng/ml. The dynamic assay range for this kit is 0.75 – 12.0 ng/ml.


  1. The role of free prostate-specific antigen in prostate cancer detection. Curr Urol Rep. (2000) 1 (1): 78-82. Review. Han M., et al.
  2. Clinical utility of measurements of free and total prostate-specific antigen (PSA): a review. Prostate Suppl. (1996) 7: 64-9. Review. Catalona W.J.
  3. Cost-effectiveness of percent free PSA for prostate cancer detection in men with a total PSA of 4-10 ng/ml. Urol Int. (2007) 79 (4): 336-44. Bermúdez-Tamayo C., et al.
  4. Prostate cancer biomarkers: an update. Urol Oncol. (2014) 32 (3): 252-60. Review. Romero Otero J., et al.
  5. Percent free prostate-specific antigen: entering a new era in the detection of prostate cancer. Mayo Clin Proc. (1997) 72 (4): 337-44. Review. Vashi A.R. and Oesterling J.E.


  • Full Name: Free Prostate Specific Antigen (Free PSA) ELISA Kit
  • Reactivity: Human
  • Sample Type: Serum, Plasma
  • Sensitivity: 0.1 ng/ml



Your secretory IgA ELISA kit gave good results and I was also really impressed with how quickly we received it.

L. Johnston
PhD Student / University of Glasgow

It is refreshing to know that you have a technical team that is very knowledgeable. I have already recommended your company to other researchers in our department.

Dr. P. Anderson
Lecturer / University College London (UCL)

I am a first time user and found that your instruction manual was very easy to follow. The insulin ELISA kit performed well and I was happy with the results that were generated.

J. Thomas
Senior Technician / Addenbrooke’s Hospital

I carried out a pilot study comparing the performance of many ELISA kits from different suppliers and found your kits to be one of the better performers. We observed good linearity and tight replicates.

Dr. C. Davies
Lead Scientists / AstraZeneca

You are my first point of contact when I am looking to purchase ELISA kits. You have such an easy and simple system, yet it is very effective.

A. Shaw
Purchasing / University of Oxford