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HelpTest Code STRC Standard Renal Clearance, Plasma and Random Urine
Specimen Required
Contact MLI for approval prior to ordering this test.
Both plasma and urine are required.
Specimen Type: Plasma
Container/Tube: 6-mL Green top (sodium heparin)
Specimen Volume: 3-4 mL
Collection Instructions: Label specimen as plasma.
Specimen Type: Urine
Container/Tube: Sarstedt 5 mL Aliquot Tube (T914)
Specimen Volume: 5 mL
Collection Instructions:
1. Collect a random urine collection.
2. No preservative.
3. Label specimen as urine.
Useful For
Precise measurement of glomerular filtration rate and renal plasma flow
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| IOTC | Iothalamate Clearance | No | Yes |
| PAHCC | PAH Clearance | No | Yes |
Method Name
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
Reporting Name
Standard Renal ClearanceSpecimen Type
Plasma Na HeparinUrine
Specimen Minimum Volume
2 mL plasma/5 mL urine
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Plasma Na Heparin | Refrigerated (preferred) | 7 days | |
| Frozen | 7 days | ||
| Urine | Refrigerated (preferred) | 7 days | |
| Frozen | 7 days |
Reference Values
GLOMERULAR FILTRATION RATE
20 years: 87-141 mL/min/SA
(Iothalmate) Decreases by 4.95 mL/min/decade
≤ 19 years: Not established
20 years: 87-141
21 years: 86-140
22 years: 86-140
23 years: 85-139
24 years: 85-139
25 years: 84-138
26 years: 84-138
27 years: 83-137
28 years: 83-137
29 years: 82-136
30 years: 81-136
31 years: 81-136
32 years: 81-135
33 years: 80-135
34 years: 80-134
35 years: 79-134
36 years: 79-133
37 years: 78-133
38 years: 78-132
39 years: 77-132
40 years: 77-131
41 years: 76-131
42 years: 76-130
43 years: 75-130
44 years: 75-129
45 years: 74-129
46 years: 74-128
47 years: 73-128
48 years: 73-127
49 years: 72-127
50 years: 72-126
51 years: 72-126
52 years: 71-125
53 years: 71-125
54 years: 70-124
55 years: 70-124
56 years: 69-123
57 years: 69-123
58 years: 68-122
59 years: 68-122
60 years: 67-121
61 years: 67-121
62 years: 66-120
63 years: 66-120
64 years: 65-119
65 years: 65-119
66 years: 65-119
67 years: 64-118
68 years: 64-118
69 years: 63-117
70-150 years: 62-116
PARA-AMINOHIPPURATE (PAH) CLEARANCE
PAH Clearance
0-19 years: not established
20-29 years: >448 mL/min/SA
30-39 years: >413 mL/min/SA
40-49 years: >378 mL/min/SA
50-59 years: >343 mL/min/SA
60-69 years: >308 mL/min/SA
70-79 years: >273 mL/min/SA
80-89 years: >238 mL/min/SA
90-99 years: >203 mL/min/SA
Note: Reference range decreases by 35mL/decade.
FILTRATION FRACTION
>or=16 years: 18-22%
Interpretation
Iothalamate Clearance:
Low glomerular filtration rate (GFR) values indicate abnormal renal function, which may be either reversible/transient or irreversible/permanent. GFR tends to decline with age.
Para-Aminohippurate (PAH) Clearance:
The renal clearance of PAH, calculated from measurements of PAH in serum and timed urine specimens, equals renal plasma flow (RPF). However, it is important to note that only 85% to 90% of PAH is cleared from the circulation in a single pass, so the PAH clearance may underestimate RPF by 10% to 15%.
Filtration Fraction (FF):
The FF is the fraction of plasma perfusing the kidneys that is filtered (FF=GFR/RPF). Under normal conditions, FF is approximately 20%. Values significantly different from this provide an index to changes in GFR relative to RPF. For example, in states of decreased renal perfusion due to congestive heart failure, both RPF and GFR are decreased, whereas the FF is >20%.
Clinical Reference
1. Seegmiller JC, Burns BE, Fauq AH, et al: Iothalamate quantification by tandem mass spectrometry to measure glomerular filtration rate. Clin Chem 2010;56:568-574
2. Slack TK, Wilson DM: Normal renal function CIN and CPAH in healthy donors before and after nephrectomy. Mayo Clin Proc 1976;51:296-300
3. Liedtke RR, Durate CG: Laboratory protocols and methods for the measurement of glomerular filtration rate and renal plasma flow. In Renal Function Tests. Edited by CG Duarte. Boston, Little Brown and Co., 1980, pp 49-63
4. Kasiske BL, Keane WF: Laboratory assessment of renal disease: clearence, urinalysis, and renal biopsy. In Brenner and Rector's The Kidney. Sixth edition. Edited by BM Brenner. Philadelphia, PA, WB Saunders Co, 2000, pp 1129-1142
5. Wilson DM, Bergert JH, Larson TS, Liedtke RR: GFR determined by nonradiolabeled iothalamate using capillary electrophoresis. Am J Kid Dis 1997;30:646-652
Day(s) Performed
Monday through Friday
Report Available
Same day/1 to 4 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
82542 x 7
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| STRC | Standard Renal Clearance | 96403-1 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| IOTC | Iothalamate Clearance | 90995-2 |
| PAHC | PAH Clearance | 96404-9 |
| FILT | Filtration Fraction | 96405-6 |
| CMT13 | Comment | 77202-0 |