What does a creatinine level of 1.23 indicate?

Interpreting a Creatinine Level of 1.23 mg/dL

A creatinine level of 1.23 mg/dL may indicate early kidney dysfunction and warrants further evaluation, especially in certain patient populations. This value is slightly elevated above the normal range for most adults and could represent Stage 1 Acute Kidney Injury or early Chronic Kidney Disease, requiring additional assessment of kidney function through eGFR calculation and clinical context.

Normal Creatinine Values and Interpretation

• Normal serum creatinine ranges:

  • Men: 0.7-1.3 mg/dL
  • Women: 0.6-1.1 mg/dL 1

• A creatinine of 1.23 mg/dL is:

  • Within the upper normal range for men
  • Above the normal range for women
  • May represent significant kidney dysfunction in elderly patients due to decreased muscle mass 1

Clinical Significance

Potential Kidney Disease Indicators

• This value could represent:
  • Stage 1 Acute Kidney Injury if it represents an increase of ≥0.3 mg/dL from baseline within 48 hours 2
  • Early Chronic Kidney Disease if persistently elevated for ≥3 months 2
  • Impaired renal function in patients with cirrhosis, as values >1.2 mg/dL are considered a risk factor for hepatorenal syndrome 2

Limitations of Isolated Creatinine Measurement

• Serum creatinine alone is an inadequate measure of kidney function 2:
  • GFR must decline to approximately half the normal level before creatinine rises above normal range
  • Affected by factors other than GFR: age, sex, race, muscle mass, diet, medications
  • May remain "normal" despite significant kidney dysfunction, especially in elderly or those with reduced muscle mass

Recommended Next Steps

1. Calculate eGFR using validated equations (e.g., MDRD or CKD-EPI) that account for age, sex, race, and body size 2

2. Assess for acute changes:

   • Compare to previous values if available
   • An increase of ≥0.3 mg/dL within 48 hours indicates Stage 1 AKI 2

3. Evaluate for risk factors and causes:

   • Medications (NSAIDs, aminoglycosides, contrast media)
   • Volume depletion
   • Urinary tract obstruction
   • Underlying chronic conditions (diabetes, hypertension)
   • Recent procedures involving contrast media

4. Additional testing if kidney dysfunction is suspected:

   • Urinalysis for proteinuria, hematuria
   • Urine albumin-to-creatinine ratio
   • Renal ultrasound if structural issues suspected

Clinical Implications in Specific Populations

Hypertensive Patients

• In hypertensive patients, a creatinine >1.2 mg/dL is associated with:
  • 3× higher 8-year mortality 3
  • Target BP should be <130/85 mmHg in patients with elevated creatinine 2
  • Only 11% of hypertensive patients with elevated creatinine achieve target BP control 4

Patients with Cirrhosis

• In cirrhosis patients, creatinine >1.2 mg/dL is:
  • A risk factor for hepatorenal syndrome 2
  • Associated with worse outcomes and may require intervention 2
  • May warrant consideration for vasoconstrictor therapy if it increases to >1.5 mg/dL (Stage 1b AKI) 2

Patients on Immune Checkpoint Inhibitors

• For patients receiving immunotherapy:
  • Creatinine 1.23 mg/dL represents Grade 1 nephritis if it's an increase of >0.3 mg/dL from baseline
  • May require temporary holding of immune checkpoint inhibitors and monitoring 2

Conclusion

A creatinine level of 1.23 mg/dL should not be interpreted in isolation but evaluated in the context of baseline values, patient demographics, and clinical presentation. eGFR calculation provides a more accurate assessment of kidney function than serum creatinine alone. Regular monitoring is essential, particularly in high-risk patients, as even small elevations in creatinine can represent significant decreases in kidney function and are associated with increased morbidity and mortality.