Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
Recently had a metabolic blood test (including Cystatin C) due to years of hypertension and borderline pre-diabetes.
The things that stand out are that my Cystatin C is .73 mg/L. However my Creatinine is unusually high at 1.31. I'm assuming that because the Creatinine is high, the EGFR is down to 68 which is alarming to me.
Would eating impact the Creatinine levels? I did have breakfast and a full lunch an hour before the blood draw.
If my Cystatin C levels are normal, could I disregard the unusually high Creatinine and low eGFR? Or are Cystatin C and Creatinine correlated?
Last edited by UniversalNotePad; 08-17-2021 at 09:39 PM..
Reason: title
Lots of questions there but those don't matter as your doctor will have all of that information in front of him and I would go by what he says.
In general serial tests mean more than just one single test. If the creatinine is going up then one needs reasons to explain that. Creatinine can go up and down based on hydration status. Usually with dehydration the BUN also becomes more elevated increasing the BUN/Creatinine ratio. The creatinine can also be impacted by thyroid status in both hyper and hypothyroidism. Creatinine can be impacted by muscle mass destruction as more creatine is created and thus converted to creatinine. If one ingests creatine as supplements then that also can cause elevated creatinine. Creatine can come from diet of high protein like animal products which make sense. It is not impacted by recent food right before testing. So thus the cystatin C.
"Cystatin C is a more sensitive marker than creatinine for the estimation of GFR in type 2 diabetic patients"
Diabetics or everybody else including those with hypertension can have a microablumin urine test (ACR) also to check for kidney involvement.
Finally the eGFR in the greater than 60 range. It isn't meant to be used in those with > 60 with regards to creatinine. It is more accurate in those with very low eGFR but not in the high range numbers. Most places report the result as > 60 and don't give a finite number in order to avoid the misinterpretation.
The expanded eGFR can include creatinine and cystatin C which is the way to go. Plug in the numbers here,
Lots of questions there but those don't matter as your doctor will have all of that information in front of him and I would go by what he says.
In general serial tests mean more than just one single test. If the creatinine is going up then one needs reasons to explain that. Creatinine can go up and down based on hydration status. Usually with dehydration the BUN also becomes more elevated increasing the BUN/Creatinine ratio. The creatinine can also be impacted by thyroid status in both hyper and hypothyroidism. Creatinine can be impacted by muscle mass destruction as more creatine is created and thus converted to creatinine. If one ingests creatine as supplements then that also can cause elevated creatinine. Creatine can come from diet of high protein like animal products which make sense. It is not impacted by recent food right before testing. So thus the cystatin C.
"Cystatin C is a more sensitive marker than creatinine for the estimation of GFR in type 2 diabetic patients"
Diabetics or everybody else including those with hypertension can have a microablumin urine test (ACR) also to check for kidney involvement.
Finally the eGFR in the greater than 60 range. It isn't meant to be used in those with > 60 with regards to creatinine. It is more accurate in those with very low eGFR but not in the high range numbers. Most places report the result as > 60 and don't give a finite number in order to avoid the misinterpretation.
The expanded eGFR can include creatinine and cystatin C which is the way to go. Plug in the numbers here,
BUN/Creatinine ratio is 14 so I don't think this number is that bad if I'm not mistaken?
My Creatinine usually hovers between the 1.0 and 1.1 range (for the past few years) so it was a surprise to see it at 1.31 with the most recent metabolic panel.
The only difference this time around when doing the blood draw was the breakfast and lunch I had right before the blood draw. And perhaps a little more exercise in the week than usual (tennis/some weight lifting).
BUN/Creatinine ratio is 14 so I don't think this number is that bad if I'm not mistaken?
My Creatinine usually hovers between the 1.0 and 1.1 range (for the past few years) so it was a surprise to see it at 1.31 with the most recent metabolic panel.
The only difference this time around when doing the blood draw was the breakfast and lunch I had right before the blood draw. And perhaps a little more exercise in the week than usual (tennis/some weight lifting).
I would not recommend testing right before a blood draw for a variety of reasons. Excessive exercise can breakdown muscle. It will probably go back down and if it doesn't then further tests might be in order like a CPK and microalbumin if not more based on your history and physical.
Control your blood pressure and blood sugar and you should be in good shape with regards to two of the big causes of renal problems.
I would not recommend testing right before a blood draw for a variety of reasons. Excessive exercise can breakdown muscle. It will probably go back down and if it doesn't then further tests might be in order like a CPK and microalbumin if not more based on your history and physical.
Control your blood pressure and blood sugar and you should be in good shape with regards to two of the big causes of renal problems.
Thanks for the additional input. Actively getting my blood pressure and blood sugar under control.
It's just strange that my Creatinine and Cystatin C are at the opposite ends of the spectrum and I'm trying to understand why that is the case. To your point, the exercise may have affected that.
If that's the case, then Cystatin C is not affected by those factors and is a more accurate representation of true kidney function/GFR?
On paper, the Creatinine is saying there's problems with my kidney but the Cystatin C is saying my kidney function is completely normal.
Last edited by UniversalNotePad; 08-18-2021 at 12:29 AM..
Thanks for the additional input. Actively getting my blood pressure and blood sugar under control.
It's just strange that my Creatinine and Cystatin C are at the opposite ends of the spectrum and I'm trying to understand why that is the case. To your point, the exercise may have affected that.
If that's the case, then Cystatin C is not affected by those factors and is a more accurate representation of true kidney function/GFR?
On paper, the Creatinine is saying there's problems with my kidney but the Cystatin C is saying my kidney function is completely normal.
Tests have limitations and there is much to be desired when it comes to endogenous clearance or markers for glomerular filtration. For a marker to be used for filtration rate the substance must be passively cleared and not be reabsorbed by the renal tubules. Creatinine was the first marker that we have more experience with. We know the flaws of creatinine and its relation to creatine. Cystatin C is a more recent marker that is not as impacted by creatine levels associated with muscle. It is more diverse in origin. There is a slight better correlation with disease states with cystatin C.
You have to keep in mind that these are just estimates and for more accurate results if they really desired to have them are exogenous rather than endogenous markers of filtration. The endogenous markers underestimate GFR.
Continue to do what you are doing. Lose weight if you are overweight and it will help you get out of metabolic syndrome if you do have it. Be careful with uric acid and gout associated with metabolic syndrome. You might want to check your diet and optimize it.
Our therapeutic toolbox, when it comes to renal function, consists of a hammer and a role of duct tape, as opposed to a complete set of Snap -Ons. There's very little we can do to treat failing renal function except to prevent/delay it as best we can by maintaining normal BS & BP as mentioned above...(For diabetics, ACEs/ARBs may help prevent nephropathy but may need to be started before it even shows itself.)
Tests like creatinine etc are more important in following the course/establishing prognosis/anticipating dialysis than in making a subtle diagnosis early in the course.
Creatinine levels vary with state of hydration, diet and recent physical activity. It varies by a few 10ths up & down with each test, so you can't make too much of small variations from one test to the next.... Even a "trend" over time is not indicative of failing kidneys until it gets consistently above the normal range. (Normal is normal-- like a Home Run is just one run regardless how far over the fence it goes.)
While renal function, like everything else, tends to deteriorate with age, but older folks tend to eat less protein, have reduced muscle mass and exercise less, so creatinine levels tend to stay in the normal range--ie- normal creat levels in the elderly may be less accurate indicators.
Please register to post and access all features of our very popular forum. It is free and quick. Over $68,000 in prizes has already been given out to active posters on our forum. Additional giveaways are planned.
Detailed information about all U.S. cities, counties, and zip codes on our site: City-data.com.
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
