From the Guidelines
A creatinine level of 1.04 and alkaline phosphatase of 127 are generally not concerning for preoperative evaluation in most patients. These values are only mildly elevated or within normal range for many laboratory reference standards. Creatinine at 1.04 mg/dL is typically within normal limits for adult males (normal range often 0.7-1.3 mg/dL) though it may be slightly elevated for females (normal range often 0.6-1.1 mg/dL) 1. Alkaline phosphatase at 127 U/L is either within high-normal range or slightly elevated depending on the lab's reference range (typically 40-130 U/L for adults).
According to the acc/aha 2007 guidelines on perioperative cardiovascular evaluation and care for noncardiac surgery, a preoperative creatinine level greater than 2 mg per dL is a significant, independent risk factor for cardiac complications after major noncardiac surgery 1. Since the patient's creatinine level is 1.04, which is below the threshold of 2 mg/dL, it is not concerning for preoperative evaluation. The American Urological Association/Endourological Society guideline also recommends evaluating serum chemistries and renal function based on clinical characteristics, including pertinent preoperative medications and therapies, endocrine disorders, and risk of renal dysfunction 1.
However, clinical context matters significantly. If these represent acute changes from the patient's baseline, if there are other abnormal lab values, or if the patient has underlying liver or kidney disease, further evaluation might be needed. The surgeon and anesthesiologist should review these values in the context of the patient's complete medical history, the type of surgery planned, and any medications that might affect kidney or liver function during the perioperative period.
Some key points to consider include:
- The patient's medical history and any underlying conditions that may affect kidney or liver function
- The type of surgery planned and its potential impact on kidney or liver function
- Any medications that may affect kidney or liver function during the perioperative period
- The presence of any other abnormal lab values that may indicate a need for further evaluation.
From the Research
Preoperative Concerns
- Creatinine levels of 1.04 and alkaline phosphatase levels of 127 may be concerning for preoperative patients, as they can indicate underlying kidney or liver issues 2, 3.
- Elevated serum creatinine levels can be a sign of renal insufficiency, and earlier referral to a nephrologist is recommended to identify and treat reversible causes of renal failure 3.
- Alkaline phosphatase levels can be elevated in patients with chronic kidney disease, and high levels have been associated with cardiovascular disease and vascular calcification 2.
Interpretation of Laboratory Results
- Serum creatinine is the most widely used functional biomarker of the kidney, but its use is associated with substantial shortcomings, and understanding these limitations is critical for accurate interpretation of creatinine values 4.
- Acute changes in serum creatinine are not always a meaningful metric in randomized controlled trials and clinical care, and may not necessarily indicate acute kidney injury 5.
- New renal biomarkers, such as neutrophil gelatinase-associated lipocalin and cystatin C, may be more accurate and reliable than creatinine for diagnosing acute kidney injury and predicting patient outcomes 6.
Clinical Implications
- Patients with elevated creatinine levels should undergo investigations to determine the potential reversibility of disease, evaluate prognosis, and optimize planning of care 3.
- Nephrologists should provide consultation in a timely manner for patients with elevated serum creatinine levels, and provide advice on urgent or emergency assessment 3.
- The use of creatinine as a marker of kidney function should be interpreted with caution, and alternative biomarkers may be considered in certain clinical contexts 4, 6.