Type of Hormone: Steroid
Extraction procedure required
Purpose of Test:
determine serum concentration of progesterone in order to obtain
information about reproductive function. Reasons to perform a
progesterone test vary with the species and include:
checking for pregnancy
checking for adequate level of progesterone to maintain pregnancy
determining if ovulation occurred
to aid in the diagnosis of reproductive disorders (i.e. retained corpus luteum)
Description of test and procedures:
The test is a radioimmunoassay performed with in-house reagents. The
radioimmunoassay technique is based on the competitive binding of the
serum progesterone and a radiolabeled progesterone preparation.
They compete for binding to an antibody specific for progesterone.
The antibody-bound radiolabeled progesterone is separated and the
quantity is determined by counting in a gamma spectrometer. Results
for the unknown are read from a curve prepared by plotting results for a
set of known standards. Sera with pre-determined concentrations are
included in every extraction procedure and assayed for quality control
Sample Needed and Procedures for Submittal:
Submit at least 1mL of serum on a cold pack.
It may be possible to perform this analysis with less serum, but
laboratory approval is required.
Schedule For Running Test:
Assay preparation begins Thursday morning and results are reported the
following Monday afternoon.
Interpretation of Results:
Please refer to Reference Values. Out of the norm results should be
interpreted by a veterinary clinician or researcher familiar with
reproductive function in the species being tested. Progesterone
level can not be used to determine pregnancy in the dog or cat since an
elevated level will be present in both pregnant and pseudopregnant
animals. In the llama, elevated progesterone at day 20 indicates
pregnancy. In the horse, elevated progesterone in a sample collected
during the period of the next expected estrus (20 days after last estrus)
indicates pregnancy. For a random sample from a mare, the more
appropriate test for pregnancy is the Mare Pregnancy Test (MPT) based on
the PMSG level. The level of progesterone necessary to maintain
pregnancy in the mare is 4.0 ng/ml.
This assay does not detect
synthetic hormones such as Regumate and MAP.