Creatinine and eGFR

Introduction

Creatinine is a waste product from the breakdown of a compound called creatine. Usually creatinine is removed from the body by the kidneys. Measurements of creatinine levels and estimation of glomerular filtration rate (eGFR) in a blood sample are useful for the evaluation of kidney function, diagnosis and monitoring of acute and chronic renal disease, and to assess the status of renal dialysis patients.

Pricing

$59

How to order a test

Synonyms

• Estimated Glomerular Filtration Rate
• Estimated GFR
• Calculated GFR

What is Included?

Measurement of creatinine levels in a blood sample by Jaffe chemistry (kinetic alkaline picrate), and estimation of glomerular filtration rate (eGFR) using the CKD-EPI Creatinine Equation (2009).

Turnaround Time

1 – 3 business days
The turnaround time is not guaranteed. The average turnaround time is 1 – 3 business days from the date that the sample arrives at the laboratory. Shipping time for the sample is not included. Additional time is required if the case requires confirmatory or reflex testing, or if the sample is insufficient, or if a recollection is required.

Related Documents

Additional Information and Resources

» Kidney function – what is normal and what is not?

Preparation Before Specimen Collection

Avoid taking antibiotics containing cephalosporin within four hours of collecting the blood specimen for this assay.

Specimen Type

Blood

Volume

50 μL in a microtainer

Container

Microtainer (regular blood tube)

Collection Method

This test requires a blood sample from a finger prick. All supplies for sample collection are provided in the kit.

1. First wash and dry hands. Warm hands aid in blood collection.
2. Clean the finger prick site with the alcohol swab and allow to air dry.
3. Use the provided lancet to puncture the skin in one quick, continuous and deliberate stroke.
4. Wipe away the first drop of blood.
5. Massage hand and finger to increase blood flow to the puncture site. Angle arm and hand downwards to facilitate blood collection on the fingertip.
6. Drip blood into the microtainer tube.
7. Dispose of all sharps safely and return sample to the laboratory in the provided prepaid return shipping envelope.

NOTES: Avoid squeezing or ‘milking’ the finger excessively. If more blood is required and blood flow stops, perform a second skin puncture on another finger. Do not touch the fingertip.

Specimen Storage

Maintain specimen at temperatures between 2°C and 30°C during storage and transport.

Specimen Stability

Blood samples can be refrigerated or kept at room temperature for up to 7 days.

Causes for Rejection

• Incorrect or incomplete patient identification
• Incorrect specimen collection
• Inappropriate storage and transport conditions
• Incorrect specimen volume
• Hemolysis

Purpose

To measure creatinine levels and estimate glomerular filtration rate in a blood sample for the evaluation of kidney function, diagnosis and monitoring of acute and chronic renal disease, and to assess the status of renal dialysis patients.

Limitations

• This report is not intended for use in medico-legal applications. 
• These results should be interpreted in conjunction with other laboratory and clinical information.
• Correct specimen collection and handling is required for optimal assay performance. 
• Interferences from medication or endogenous substances may affect results.
• Antibiotics containing cephalosporin lead to inaccurate results if blood sample is taken within four hours of an antibiotic dose.
• Low creatinine levels can also occur during pregnancy, in individuals who have a low muscle mass or a diet very low in protein, due to certain medications, or they may be an indication of certain types of severe liver disease.
• Elevated creatinine can also be caused by dehydration, increased protein intake (e.g., > 225 g meat in the 24 hours before sample collection), muscle injury, and recent intense exercise.

Methodology

Jaffe chemistry (kinetic alkaline picrate) (Alinity c Creatinine assay) for the measurement of creatinine levels and the CKD-EPI Creatinine Equation (2009) to calculate eGFR.

Reference Intervals

Normal creatinine ranges are 0.72 – 1.25 mg/dL for adult males and 0.57 – 1.11 mg/dL for adult females.

Normal GFR is more than 90 for adults. GFR declines with age, even in the absence of kidney disease. Values between 60 and 89 may indicate kidney disease. Values less than 60 for more than 3 months occur during moderate-to-severe chronic kidney disease.

These reference ranges were obtained from the Alinity c Creatinine package insert and the National Kidney Foundation.