I would definitely get the ultrasound done.
I'm sorry to throw so much at you but CKD hasn't so many "moving parts". Right now, I would focus on getting the P level down and dealing with the anemia. Tanya's can be overwhelming and there is a lot to read. It's a steep learning curve.
Sorry...I read you all talking about BFF so I thought you had it. Here are Tanya's
food tables for the U.K. I don't know if that means these brands are more likely available in Singapore. The only issue is she doesn't have the carbs on this table like she does the US table.
Yes...you can use the RX Vitamins for Pets Phos Bind. It is aluminum hydroxide powder. I didn't realize you already had it. So you're fine to use it. Just be sure you read what I left you on dosing because it's really important. If it were me, I'd go with the middle of the road on binder dosage to start with. That would be 60 mg/kg or 27 mg/lb of kitty weight for a P level at 7. A loosely packed 1/4 tsp of aluminum hydroxide is 300 mg. You don't have to be exact on aluminum hydroxide so don't worry if you get it a little more than loosely packed. If your kitty weighs 10 lbs, for example, I'd round up and give 1/4 tsp daily. I would just measure out the amount in the morning and sprinkle some on each meal and mix in just being sure that all is used by the end of the day. You should have his P levels rechecked 10-14 days after starting binder, and if it's not down, than the binder dose needs to go up.
If he will eat a lower P food, it's important that you do both...lower P food and binder. I have fought a similarly high P level in my first CKD cat and I can tell you that it is not easy. You can't just dump binder on any food and hope to make progress of the kind you need to make. Again....that's if he will eat a lower P food. If he will not, then you have to deal with what you have because the best food for a cat is the one it will eat and that is especially true for a CKD cat. Personally, I would not have used a binder to drop P from 4.5 down. You don't need binders until the P gets to around 6; low P food can keep the P level down below 4.5 if that's where the numbers are starting. But if the P level is starting at 6 or 7, it takes more effort to bring the numbers down to 4.5.
Also be aware that the binder can be constipating. I did not have this issue in any of my cats but ECID? It's also important that you and your vet monitor the MCV value in his labs since he is already anemic and use of aluminum hydroxide binders can affect this through aluminum toxicity. I've used binders for years in cats and not had an issue with aluminum toxicity but be aware. Watch for any drop in MCV.
I'm not surprised that he benefitted from a subq session and I'm also not saying he doesn't have pancreatitis or some other condition besides CKD that would benefit from temporary subq fluids. I'll let you read Tanya's on
Subq fluids and you can decide. Again, for some other condition besides CKD, he might benefit from temporary subqs. But, sometimes, when kitties are stable with CKD, you could be giving fluids a very long time and you can build up scar tissue. One of my stable CKD cats got subqs daily for four years. So it's important to heed what is said on Tanya's about subqs for CKD.
Cats cannot absorb cyanocobalamin orally and so it is usually given as an injection but this type of B12 helps with intestinal issues, not anemia. I am not familiar with those tablets but I feel it's just the iron you want because he is iron deficient, I'd look at some of the iron products on Tanya's under
anemia. If you scroll way down on that page, she discusses iron deficiency and also the kind of treatment needed for anemia depending on the hematocrit. If he is not iron deficient, he doesn't need iron for the anemia.....he needs the B Vitamins. And if he has any kind of infection, he should not be getting iron.
The reason he also needs some kind of multiB is because B3, B6, B9, and B12 are all need for red blood cell regeneration and all will help with anemia. For all four of my CKD cats, I never had to do anything for anemia except give methylB12 and a multiB. Back then, the Jarrows BRight did not have the issue of P in the formula and none of my cats were diabetic. However, when my last CKD cat crossed, I sent the capsules I had made with the methylB12 and Jarrows to an FDMB member and it did not raise her cat's BG. When her cat crossed, she sent the remainder to another FDMB member and it also did not raise the BG. It's such a minuscule dose. Of more concern to me is the P becausemyou don't want to add more P when you are fighting P. I still don't believe the amount of P is that great because it's a tiny amount of multi B they get. It would only add 2.8mg of P per day. If it were me, I'd try to find some of the other products or find the older Jarrows without the phosphorus and if I couldn't, I'd just give the Jarrows. I don't think it will raise his P level but you can give more binder if necessary. If it raises his BG, you can tweak the insulin. But what is more difficult is if his HCT drops below 20% and you have to start erythropoietin stimulating agents. That's a whole different ballgame.
You can't tell from this data. You need mg P/100 kcal or the percent on a dry matter basis.
I'm not familiar with this group. The one I belonged to and learned so much....they were amazing....was the yahoo cRF group. Whether members have moved over to FB or not, I'm not sure.
Another long post...I'm sorry and I hope I've answer your questions. Pls let me know.
but if you are up for it, do you have any information you can share? 
