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Chronic Kidney Disease Graph analysis question (1 Viewer)

hasti rostmami

New Member
Sep 23, 2019

After examining Sally-Anne’s symptoms, her nephrologist requested further tests. The results of her Serum Creatinine test and Creatinine Clearance test gave a GFR value of 20. The following graphs show some relationship between Serum Creatinine, Creatinine Clearance and eGFR (estimated Glomerular Filtration Rate) for CKD patients.
You are Sally-Anne’s nephrologist and are required to explain to her the importance of these lab tests in determining the severity of her CKD. Sally-Anne would like to know a brief description of each lab test, what the test results mean and how a relevant GFR is determined. You may analyse the data in graphs provided to help answer Sally-Anne’s questions.

How do you answer this question? What do the graphs show? what kinds of tests are they. HELP PLEASE :D

Eagle Mum

Well-Known Member
Nov 9, 2020
The bottom graph tracks an individual’s (Sally-Anne’s) serum creatinine level, creatinine clearance and estimated glomerular filtration rate over 8 days.

Her serum/blood creatinine level (blue triangle data points) is progressively linearly increasing which indicates that her kidneys are not clearing creatinine (green squares), a constant by-product of muscle metabolism to store and utilise energy, reflecting the declining ability of her kidneys to filter creatinine and other substances circulating in her blood (purple diamonds).

The decline in her kidney function is happening quite rapidly, so her nephrologist (kidney specialist), needs to treat her immediately to try and reverse whatever disease process is going on and hopefully preserve as much kidney function as possible.

The top graph shows the general relationship between creatinine and glomerular filtration rate which is an inverse exponential graph.

It shows that a filtration rate > 90mL/min/m^2 maintains a normal creatinine level of < 1.0 mg%.

As filtration rate decreases, serum/blood creatinine starts to accumulate but down to about 50 mL/min/m^2, kidneys are reasonably able to filter out creatinine to maintain relatively stable blood levels of <1.8 mg%, with the graph showing that most people who donate a kidney are stable within that range.

Once filtration rate gets below 50 mL/min/m^2, the kidneys aren’t clearing creatinine sufficiently and so it rapidly accumulates.

Creatinine itself is not a particularly toxic substance, but its level & clearance, from which GFR can be inferred, indicate similar loss of kidney function in filtering out other water soluble waste products (many of which are toxic), so without urgent treatment, Sally-Anne will rapidly become very sick.
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