Calculation to measure the protein catabolic rate
Estimation of dietary protein intake
Only orderable as part of a profile. For more information see SAT24 / Supersaturation Profile, 24 Hour, Urine.
Calculation
pctr
Urine
Only orderable as part of a profile. For more information see SAT24 / Supersaturation Profile, 24 Hour, Urine.
1 mL
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability. |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Urine | Refrigerated (preferred) | 14 days | |
Frozen | 30 days | ||
Ambient | 7 days |
Calculation to measure the protein catabolic rate
Estimation of dietary protein intake
Urine is often supersaturated, which favors precipitation of several crystalline phases such as calcium oxalate, calcium phosphate, and uric acid. However, crystals do not always form in supersaturated urine because supersaturation is balanced by crystallization inhibitors that are also present in urine. Urinary inhibitors include ions (eg, citrate) and macromolecules but remain poorly understood.
Urine supersaturation is calculated by measuring the concentration of all the ions that can interact (potassium, calcium, phosphorus, oxalate, uric acid, citrate, magnesium, sodium, chloride, sulfate, and pH). Once the concentrations of all the relevant urinary ions are known, a computer program can calculate the theoretical supersaturation with respect to the important crystalline phases (eg, calcium oxalate).(1)
Since the supersaturation of urine has been shown to correlate with stone type,(2) therapy is often targeted towards decreasing those urinary supersaturations that are identified. Treatment strategies include alterations in diet and fluid intake as well as drug therapy, all designed to decrease the urine supersaturation.
Only orderable as part of a profile. For more information see SAT24 / Supersaturation Profile, 24 Hour, Urine.
56-125 g/24 hours
Increased protein intake, reflected by an increased protein catabolic rate, may increase the risk of kidney stone formations.
No significant cautionary statements
1. Werness PG, Brown CM, Smith LH, Finlayson B: EQUIL2: a BASIC computer program for the calculation of urinary saturation. J Urol. 1985;134:1242-1244
2. Parks JH, Coward M, Coe FL: Correspondence between stone composition and urine supersaturation in nephrolithiasis. Kidney Int. 1997;51:894-900
3. Ferraro PM, Mandel EI, Curhan GC, Gambaro G, Taylor EN: Dietary protein and potassium, diet-dependent net acid load, and risk of incident kidney stones. Clin J Am Soc Nephrol. 2016 Oct 7;11(10):1834-1844. doi: 10.2215/CJN.01520216
This test is a calculation for protein catabolic rate. The calculation is performed in the laboratory information system, SCC Soft.
Monday through Friday
Not Applicable
Calculation only
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
PCTR | Protein Catabolic Rate, U | 93746-6 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
PCTR | Protein Catabolic Rate, U | 93746-6 |