Low GFR High Creatinie

[Medic6919]

My fiance is 37y/o male who for the past year has had a GFR level of 57mL/min with Creatinie level of 1.4mg/dL, all other lab results are in normal range. I'm worried because his mother was diagnosed with lupus in her early 40's and at age 52 died from it. He is very health, has been lifting weights for the past year, healthy diet, weighs 185LB and has no medical problems beside this issue, and has no complaints. He keeps himself well hydrated and has no problem urinating and or blood in his urine. He is scheduled for a ultrasound of his kidney next week. Blood work has been taken to check for lupus. I'm worried it may be lupus, what else can cause the abnormal levels?? please help.
THANK YOU - Medic6919

[Londres70]

I think this might be the cause of the two abnormal kidney labs.  I would recommend he stop these protein supplements/supplements for muscle building and follow up with the kidney US.  

[Medic6919]

thank you Londres70 for answering, he drinks protein shakes and does take multiple supplements

[Londres70]

Does he use any protein supplements for building muscle mass?