Low phosphorus

Hello, my 7 year old neutered chihuahua was diagnosed with b2 Myxomatous Mitral Valve Disease in April this year. I got bloods done when he was in for cardiac investigation and just recently in October. Im very confused my vet said bloods are fine but upon looking he has low phosphorus. Should I be worried? 0.77 in April and 0.73 in October. Thank you

Hello and thank you for this question.  This is definitely something to follow up with your vet.  Sometimes, depending on the blood machine, Phosphorus readings can be simply unreliable.  However, low phosphorus can be significant, particularly given two consecutive readings.  So, if they are concerned about the phosphorus level ( they can chat this over with a pathologist if they are unsure) then your vet may ask to test the phosphorus in another way.