Lab

Serum Creatinine

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Serum Creatinine, Creatinine, S-Creatinine, Standardized Creatinine

  • See Also
  1. Serum Cystatin C
  • Normal
  1. Adults
    1. Men: 0.8 to 1.3 mg/dl
    2. Women: 0.6 to 1.0 mg/dl
  2. Children (under age 20 years)
    1. Boys: 0.35 + (age in years)/40
    2. Girls: 0.35 + (age in years)/55
  • Protocol
  • New
  1. Standardized Creatinine (S-Creatinine)
    1. New, more accurate technique for measuring Serum Creatinine
    2. Not as affected by interfering substances
    3. Expect a drop in Serum Creatinine of 20% when switching to S-Creatinine measurement
  • Pathophysiology
  1. Increases by 1.0-1.5 mg/dl/day if no Renal Function
  2. Often unchanged until 25-50% of Renal Function lost
  3. Doubled Serum Creatinine implies 50% Renal Function
  • Increased
  1. Renal Insufficiency
  2. Decreased renal perfusion
  3. Urinary Tract Infections
  4. Skeletal muscle Trauma or Rhabdomyolysis
  5. Ketonemia
  6. Diabetic Ketoacidosis
  7. Creatine Supplementation >15-20 grams per day
    1. May increase Serum Creatinine over 2.0
  8. Medications (Inhibit tubular secretion of Creatinine)
    1. Aminoglycosides
    2. Cephalosporins
      1. Cefoxitin
      2. Cephalothin
    3. Hydantoin
    4. Diuretics
    5. Methyldopa
    6. Cimetidine
    7. Trimethoprim
  • Decreased
  1. Decreased muscle mass
  2. Pregnancy