Does It Matter What Progesterone Machine My Dog’s Blood Is Tested With?
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When breeders are monitoring progesterone levels to determine the optimal time for mating or insemination one of the most common questions is whether the type of progesterone machine used makes a difference. The short answer is yes, it can.
Different progesterone analysers use different testing methods and calibration systems. As a result, the numerical value reported by one machine may not be exactly the same as that reported by another, even when testing the same blood sample. This does not necessarily mean one result is wrong; it simply reflects differences in the technology used.
For this reason, consistency is key. Ideally, all progesterone tests during a breeding cycle should be performed using the same analyser and laboratory whenever possible. This allows trends in progesterone levels to be interpreted accurately and reduces the risk of confusion when making breeding decisions.
It is also important for bitch owners to understand that progesterone testing is not about chasing a single “magic number.” Breeders will often hear recommendations that a bitch should be bred or inseminated at a specific progesterone value, but these figures can vary depending on the analyser being used. Becoming overly focused on reaching an exact number can sometimes create unnecessary stress and may even lead to missed opportunities if the overall picture is ignored.
Veterinarians do not rely solely on a single progesterone value. Results are interpreted alongside the bitch’s breeding history, clinical signs, vaginal cytology findings, and, most importantly, the pattern of progesterone changes over time. Monitoring how progesterone rises through the cycle is often far more informative than focusing on one isolated result.
Modern in-house progesterone analysers used by veterinary practices can provide rapid and reliable results, allowing timely decision-making. However, because reference ranges and ovulation thresholds may vary slightly between machines, veterinarians use machine-specific guidelines when advising on breeding timing.
29th June 2026
