From the Guidelines
Toxicology causes of falsely low creatinine concentrations include interference from certain substances that affect laboratory assays, such as hyperbilirubinemia and hemolysis, as well as conditions like muscle-wasting and reduced creatinine generation. When evaluating creatinine levels in the context of toxicology, it's crucial to consider factors that can lead to falsely low readings. According to the study published in Kidney International 1, several factors can cause a false reduction in creatinine levels, including Jaffe assay interference, hyperbilirubinemia, and enzymatic interference. Some key points to consider include:
- Interference from certain substances can lead to inaccurate creatinine measurements
- Conditions like muscle-wasting and reduced creatinine generation can also result in falsely low creatinine levels
- Hyperbilirubinemia and hemolysis are specifically mentioned as causes of false reduction in creatinine levels 1
- The study highlights the importance of considering these factors when interpreting serum creatinine levels, especially in the context of possible acute kidney injury. In clinical practice, when encountering unexpectedly low creatinine values in toxicology cases, it's essential to consider alternative measurement methods, such as enzymatic assays, to ensure accurate results and avoid delaying necessary treatment.
From the Research
Toxicology Causes of Falsely Low Creatinine Concentrations
The following substances can cause falsely low creatinine concentrations:
- Carbonyl compounds, which interfere with the Jaffé reaction 2
- Dopamine, which interferes with both the Jaffé reaction and enzymatic methods 2, 3
- Cephalosporins, such as cephalothin, cephaloridine, and cefoxitin, which interfere with the Jaffé reaction 2, 4, 5
- Bilirubin, which interferes with both the Jaffé reaction and enzymatic methods 2
- Creatine, which interferes with enzymatic methods 2
- Ascorbic acid, which interferes with enzymatic methods 2
- Sarcosine, which interferes with enzymatic methods 2
- Catecholamines, such as epinephrine and norepinephrine, which cause negative interference with enzymatic creatinine assays 3
- Glucose, which demonstrates positive interference in the Jaffé method 6
- Hemolysis, which produces negative interference in the enzymatic method 6
Mechanisms of Interference
The mechanisms of interference vary depending on the substance and the method used to measure creatinine. For example:
- Cephalosporins react with alkaline picrate solution to give a creatinine-like response 5
- Dopamine and dobutamine reversibly adhere to the catheter lumen, causing significant negative interference with the Roche enzymatic creatinine assay 3
- Glucose and hemolysis contribute to the variance in results between Jaffé and enzymatic serum creatinine methods 6