Creatinine
CPT Code(s):
82565
Turnaround Time:
4 hours
Specimen Requirements
Preferred Specimen:
Serum
Minimum Volume:
1.0 mL
Transport Container:
Serum Separator Tube (SST) or Red Top Tube
Transport Temperature:
Room Temperature
Collection Instructions:
Allow blood to clot completely prior to centrifugation. Separate serum from cells within 45 minutes of collection.
Rejection Criteria:
Citrate, Fluoride,Sodium Heparin, or EDTA plasma specimen; gross hemolysis; lipemia; improper labeling
Stability Criteria
Room Temperature:
24 hours
Refrigerated:
7 days
Frozen:
90 days
Clinical Significance
Creatinine holds specific clinical significance and diagnostic use in the field of nephrology and kidney function assessment. This test measures the level of creatinine, a waste product produced by muscle metabolism, in a patient's blood or urine.
The clinical significance and diagnostic use of Creatinine include:
1. Assessment of Kidney Function: Creatinine is primarily used to evaluate kidney function. Creatinine is filtered by the kidneys and excreted in urine, making it an important marker for estimating glomerular filtration rate (GFR), which reflects the kidneys' ability to filter waste products from the blood. Elevated levels of creatinine in the blood can indicate impaired kidney function or decreased GFR, suggesting the presence of kidney disease or dysfunction.
2. Diagnosis and Monitoring of Kidney Disease: Creatinine plays a crucial role in the diagnosis and monitoring of kidney diseases. Progressive kidney damage or disease can lead to a decrease in GFR and an increase in blood creatinine levels. Serial measurements of creatinine levels help healthcare providers assess the severity of kidney disease, track disease progression, and monitor the effectiveness of treatment interventions.
3. Calculation of Estimated GFR: Creatinine levels are used in formulas to estimate glomerular filtration rate (eGFR), which is an important measure of kidney function. eGFR provides an estimation of how well the kidneys are functioning and can help classify the stages of chronic kidney disease (CKD). Creatinine, in combination with patient demographics (age, gender, and race), is used to calculate eGFR, allowing healthcare providers to assess kidney function and classify the severity of CKD.
4. Medication Dosing and Monitoring: Creatinine is utilized in medication dosing and monitoring, especially for drugs that are cleared by the kidneys. Kidney function plays a crucial role in the elimination of many medications, and dosages need to be adjusted based on renal function. Creatinine levels provide a reliable marker for estimating renal clearance and guide appropriate dosing adjustments to avoid drug accumulation or toxicity.
5. Preoperative Evaluation: Creatinine is commonly performed as part of preoperative evaluations. It helps assess a patient's kidney function before undergoing surgery or procedures that may put additional stress on the kidneys. Evaluation of kidney function is important in determining the patient's ability to tolerate anesthesia and surgical stress and guides perioperative management.
In summary, Creatinine has specific clinical significance in the assessment of kidney function, diagnosis and monitoring of kidney disease, calculation of estimated GFR, medication dosing and monitoring, and preoperative evaluation. By measuring creatinine levels in the blood or urine, this test provides valuable information for clinical decision-making, enabling healthcare providers to assess kidney health, diagnose kidney disorders, guide treatment interventions, optimize medication management, and ensure patient safety during surgical procedures.