| Test | : | e-GFR Panel (>/=19 y/o) |
| Other Test Request Name | : | - Estimated Glomerular Filtration Rate
- eGFR
|
| Test Composition | : | - Cystatin
- Serum Creatinine
- Estimated GFR (CKD-EPI)
|
| Intended Use | : | - The estimated glomerular filtration rate (eGFR) is used to screen for and detect early kidney damage, to help diagnose chronic kidney disease (CKD), and to monitor kidney status.
- May provide more accurate estimates of kidney function in patients with differences in diet, extremes of muscle mass (such as body builders or patients with muscle wasting)
- May also prove useful in estimating change in eGFR over time in people with changing muscle mass or diet.
- May have a role in identifying persons with CKD who have the highest risk for complications.
- This equation is used for patients 18 years old and older.
|
| Methodology | : | - Creatinine:Enzymatic
- Cystatin C:Particle-Enhanced Turbidimetric Immunoassay (PETIA)
- Estimated GFR (CKD-EPI): Calculated based on CKD-EPI CREATININE-CYSTATIN EQUATION (2012)
|
| Laboratory Section | : | Chemistry |
| Special Instructions/Patient Preparations | : | - Refrain from eating a high meat diet and doing strenuous physical activity 8-12 hours before blood extraction.
- Refrain from taking medicines such as Acetaminophen (Paracetamol), N-acetyl-p-benzoquinone imine (NAPQI) metabolites, N-Acteylcysteine (NAC), Metamizole (Novaminsulfone, Dipyrone), 4-aminoantipyrine (4-AAP) and 4-Methylamino-antipyrine (4-MAP) metabolites 8-12 hrs before sample collection.
Note:If recommended preparation is not followed, you may accept but NOTE in clinical info. |
| Collection/Sample Container | : | Red or Gold tube |
Specimen and Volume Requirement
Note:Follow tube manufacturer recommendation. | : | 1-3 mL Serum |
| Alternative Specimen and Volume Requirement | : | 1-3mL Plasma (Li-heparin) |
| Specimen Stability | | |
| • Room Temperature (15-25°C) | : | 2 Days |
| • Refrigerated Temperature (2-8°C) | : | 7 Days |
| • Freezer Temperature (-20°C) | : | 1 Month |
| Transport Temperature | : | Transport specimen at 2 – 8 °C (with cold packs) |
| Rejection Criteria | : | - Specimens that failed serum index (hemolyzed and lipemic)
- Exceeded sample stability requirement
- Quantity not sufficient
- Improperly labeled specimen
- Improper collection tube used
|
| Running Day | : | Tuesday and Friday |
| Cut Off Time | : | Monday to Saturday:6:00 PM |
| TAT/Releasing of Results | : | RUNNING TIME:6:00 AM onwards RELEASING TIME: ROUTINE: 4 hours after receipt of specimen/ arrival of messenger STAT: After 2½ hours from extraction/messenger arrival |
| Reference Interval/Result Interpretation | : | CREATININE:
0-2 Months: 27.00-77.00 umol/L (0.31-0.87 mg/dL)
2M & 1 Day - 1Y: 14.00-34.00 umol/L (0.16-0.38 mg/dL)
1Y & 1 Day - 3Y: 15.00-31.00 umol/L (0.17-0.35 mg/dL)
3Y & 1 Day - 5Y: 23.00-37.00 umol/L (0.26-0.42 mg/dL)
5Y & 1 Day - 7Y: 25.00-42.00 umol/L (0.28-0.47 mg/dL)
7Y & 1 Day - 9Y: 30.00-47.00 umol/L (0.34-0.53 mg/dL)
9Y & 1 Day - 11Y: 29.00-56.00 umol/L (0.33-0.63 mg/dL)
11Y & 1 Day - 13Y: 39.00-60.00 umol/L (0.44-0.68 mg/dL)
13Y & 1 Day - 15Y: 40.00-68.00 umol/L (0.45-0.77 mg/dL)
15Y & 1 Day - 999Y MALE: 59.00-104.00 umol/L (0.67-1.18 mg/dL)
15Y & 1 Day - 999Y FEMALE: 45.00-84.00 umol/L (0.51-0.95 mg/dL)
Cystatin C: - 0~49 Y/O Male: 0.31~0.79 mg/L
- 0~49 Y/O Female: 0.40~0.99 mg/L
- 50~999Y/O Male: 0.41~0.99 mg/L
- 50~999Y/O Female: 0.40~0.99 mg/L
Estimated GFR:>60 mL/min/1.73m^2 |
| Limitations/Interferences | : | -Creatinine-based estimating equations are not recommended for use with: - Individuals with unstable creatinine concentrations. This includes pregnant women; patients with serious co-morbid conditions; and hospitalized patients, particularly those with acute renal failure. Creatinine-based estimating equations should be used only for patients with stable creatinine concentrations.
- Persons with extremes in muscle mass and diet. This includes, but is not limited to, individuals who are amputees, paraplegics, bodybuilders, or obese; patients who have a muscle-wasting disease or a neuromuscular disorder; and those suffering from malnutrition, eating a vegetarian or low-meat diet, or taking creatine dietary supplements.
- Rifampicin, Levodopa and Calcium dobesilate (e.g. Dexium) cause artificially low creatinine results. Dicynone (Etamsylate) at therapeutic concentrations may lead to falsely low results. - N-ethylglycine at therapeutic concentrations and DL-proline at concentrations ≥ 1 mmol/L (≥ 115 mg/L) give falsely high results. - 2-Phenyl-1,3-indandion (Phenindion) at therapeutic concentrations interferes with the assay. - In very rare cases, gammopathy, in particular type IgM (Waldenstrom’s macroglobulinemia), may cause unreliable results. - Acetaminophen intoxications are frequently treated with N-Acetylcysteine. N-Acetylcysteine at a plasma concentration above 333 mg/L and the Acetaminophen metabolite N-acetyl-p-benzoquinone imine (NAPQI) independently may cause falsely low results. - Venipuncture should be performed prior to the administration of Metamizole. Venipuncture immediately after or during the administration of Metamizole may lead to falsely low - Bilirubin, conjugated: 66 mg/dL(1128.6 umol/L) - Bilirubin, unconjugated: 60 mg/dL (1026 umol/L) - Hemoglobin: 1000 mg/dL (10 g/L) - Intralipid: 1000 mg/dL (10 g/L) - Rheumatoid factor: 500 IU/mL (300 kU/L) |
| Frequently Asked Questions (FAQs) | : | Q:How is it used? A: A cystatin C test may be used as an alternative to creatinine and creatinine clearance to screen for and monitor kidney dysfunction in those with known or suspected kidney disease. It is most useful in special cases where creatinine measurement could be misleading. Examples are patients with liver cirrhosis, are very obese, are malnourished, practice a vegetarian diet, have amputated limbs, or have reduced muscle mass (elderly and children). Cystatin C is not affected by body mass or diet, and hence is a more reliable marker of kidney function than creatinine. Measuring cystatin C may also be useful in the early detection of kidney disease when other test results (eGFR, creatinine or urine albumin) may still be normal or borderline and an affected person may have few, if any, symptoms. In this case, the healthcare practitioner may want to confirm if chronic kidney disease is present by measuring cystatin c. Q:What does the result mean? A: A high level of cystatin C in the blood corresponds to a decreased glomerular filtration rate (GFR) and hence to kidney dysfunction. Since cystatin C is produced throughout the body at a constant rate and removed and broken down by the kidneys, it should remain at a steady level in the blood if the kidneys are working efficiently and the GFR is normal. Recent studies suggest that increased levels of cystatin C may also indicate an increased risk of heart disease, heart failure, and mortality. Q:What are the limitations of Cystatin Test? A: Although cystatin C is less variable and less affected by age, body mass, and diet than creatinine in some individuals, it is not a perfect test and can be affected by a number of drugs and other medical conditions. Some studies have reported increased cystatin C levels associated with higher levels of C-reactive protein (CRP) or body mass index (BMI), hyperthyroidism, steroid use, malignant diseases, HIV/AIDS, rheumatic diseases, and certain metabolic conditions such as hyperhomocysteinemia (increased homocysteine). In addition, other studies suggest that cystatin C can be cleared by non-kidney pathways, such as in the gut, and that its levels tend to fluctuate among patients with kidney transplants. Q: Can Cystatin C be measured in urine samples? A: No. Unlike creatinine, cystatin C is reabsorbed from the glomerular filtrate and then metabolized in the kidneys. Under normal conditions, cystatin C is not found at detectable levels in the urine. |
| Related Words/Test | : | BUN, Creatinine Clearance, Comprehensive Metabolic Panel, Basic Metabolic Panel, Urinalysis, Urine Protein to Creatinine Ratio, Urine Albumin and Urine Albumin/Creatinine Ratio, Renal Panel, Beta-2 Microglobulin |
