Progesterone ELISA Test Kit

Ridgeway Science produce progesterone ELISA test plates as a breeding aid primarily for dairy farms. The plates can also be used in many other veterinary applications including but not limited to; horses, sheep, pigs, dogs and even camels and alpacas.

What is an ELISA test?

An ELISA test, an Enzyme-Linked Immunosorbent Assay is a biochemical technique used mainly in immunology to detect the presence of an antibody or an antigen in a sample. We use it for progesterone testing so that we can determine the level of progesterone in a sample of milk, plasma or serum.

Why use a progesterone ELISA test kit?

By confirming the progesterone level in a sample of milk, plasma or serum we can help vets, researchers and farmers to know exactly at which stage in the oestrus cycle a particular animal is. This can aid correctly timed insemination, early pregnancy indication and can give information on the presence and type of ovarian cysts. The advantage to the farmer is huge, with the potential to save hundreds of pounds in lost revenue.

For vets the test can be used as a quantitative aid alongside normal scanning and palpations to give a more complete picture. It can also be used as an aid to help diagnose cystic ovaries. And whether it is a follicular cyst or cystic corpus luteum, due to either prolonged low or high progesterone level respectively.

How it works

Each progesterone ELISA test kit uses a 96 well ELISA microplates coated with an antibody with a high specificity for progesterone. Samples of milk (e.g. dairy cows, goats, sheep) or serum/plasma (e.g. horses, dogs, camels) are added to each well along with an enzyme conjugate label. This is then left to incubate for an hour before washing the plate and adding a substrate. The subsequent reaction produces a colour change which is inversely proportional to the amount of progesterone in the sample i.e. a strong colour means low progesterone.

The Ridgeway ELISA test is available in three different formats for laboratory and on farm use:

M-Plate – milk progesterone test – laboratory use

The M-Plate measures the amount of progesterone in milk samples. This can be carried out quantitatively using the same method as the P-Plate with a full set of standards. Or semi quantitatively.
Semi quantitative [giving high/medium/low type results] measurements are obtained by using two milk standards and comparing the development of the samples with the standards by eye. The kit comes with two standards (2 and 20ng/ml) for semi quantitative use.

P-Plate – plasma or serum progesterone test – laboratory use

The P-Plate quantitatively measures (giving numerical values) progesterone in plasma or serum samples. The kit is designed for use in a laboratory setting. Each set of samples is run alongside a set of standards which are of predetermined concentration which produce a standard curve when read with an absorbance plate reader. This allows a simple computer program to calculate accurate values for the amount of progesterone in each sample.

Heataid – milk progesterone ELISA kit – on farm use

Heataid is a qualitative progesterone test kit using milk samples. It is specifically designed to be used by farmers or vets in an on-farm setting for heat detection in cows. Read more about Heataid here


Standards are created using milk, plasma or serum from an anoestrus or ovariectomised animal in which there will be little or negligible amounts of progesterone. Standards are species specific. Different species have slightly different blood/milk composition and since certain compounds can inhibit the binding of progesterone standards samples must be like for like. Progesterone is added respectively in known volumes to create a set of known concentration standards. Standards can also be provided in buffer upon request.


Standards are made from whole milk collected from an animal in oestrus with very low progesterone. The standard curve is designed to show the greatest colour distinction between 2 – 8ng/ml progesterone. The M-Plate comes with the 2&20ng/ml standard. When using these a semi-quantitative result can be gained. A full set of standards (0, 1, 2, 5, 10, 20, 50ng/ml) can be purchased enabling a quantitative analysis to be run. The standards are preserved with Sodium Azide tablets. They must be stored at a temperature of 2-8°C. They remain viable for 3 months after manufacture.


Depending on the samples to be analysed standards are made from either plasma or serum from an anoestrus animal.
The standard curve is designed to show the greatest colour distinction between 1 – 4ng/ml progesterone. The P-Plate should be run with a full set of standards (0, 0.5, 1, 2, 5, 10, 20ng/ml) enabling a quantitative analysis to be run. Samples should be stored frozen (-10 to -36°C) ensure thorough mixing after thawing.

Buffer standards are also available for both M-Plates and P-Plates.

Laboratory Services

Ridgeway Science also offers a professional laboratory progesterone ELISA assay service for universities, research institutes and corporations:

  • Gold standard ELISA test plates
  • Quick turnaround testing or batch sample service
  • Optional expert interpretation of results
  • Competitive prices
  • Good Clinical Practice (GCPv) compliant laboratory


For more information, please get in contact on 01594 530809 or