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creatinine in serum/plasma

Reference interval: - 0.6-1.4 mg/dL, 53-106 umol/L (adult) - 0.3-0.6 mg/dL, 27-53 umol/L (children < 2 years) * Conversion factor mg/dL to umol/L = 88.4 Indications: - assessment of renal disease (renal function) Clinical significance: - serum creatinine & urinary creatinine excretion are a function of lean body mass in normal persons - little or no response to dietary changes - serum creatinine is higher in men than in women - a small amount of creatinine in urine is due to tubular secretion - serum creatinine & a 24 hour urine creatinine excretion can be used to estimate the glomerular filtration rate (GFR) - significant loss of renal function at higher GFR may result in only small changes in serum creatinine [5] Increases: 1) decreased glomerular filtration - acute or chronic renal failure - urinary tract obstruction - reduced renal blood flow - shock - dehydration 2) increases independently of glomerular filtration a) ketoacidosis: acetoacetate interferences with Jaffe reaction b) massive rhabdomyolysis c) high meat intake d) supplementary creatine e) sustained exercise f) certain pharmaceutical agents - inhibition of proximal tubule secretion - probenecid - cimetidine - trimethoprim - cobicistat - dolutegravir - bictegravir - interference with Jaffe reaction - cefoxitin (possibly other cephalosporins) - ketone bodies (acetoacetate) - isopropyl alcohol - methanol - ascorbate - barbiturates - glucose - levodopa - methyldopa - flucytosine - bilirubin - cephalosporins - amphotericin B (in vivo effect) - kanamycin (in vivo effect) Decreases: 1) debilitation 2) decreased muscle mass - low serum creatinine is associated with sarcopenia & frailty [9] - low preoperative serum creatinine is associated with higher risk of major postoperative complications & 30 day mortality [9] 3) N-acetylcysteine 4) cirrhosis [5] 5) exercise may cause an increased creatinine clearance* * creatinine clearance is unreliable if the urine flow is low. Principle: See creatinine in body fluid Specimen: The recommended specimen is 10 uL of serum or plasma Serum or Plasma Specimens: Collect by standard venipuncture technique. No special patient preparation is necessary. Lithium or sodium heparin may be used as an anticoagulant for plasma specimens. Special Precautions: Potassium oxalate/sodium fluoride, citrate, & EDTA should not be used as anticoagulants. Remove serum or plasma promptly from the clot or cells. Refrigerate specimens at 2-8 degrees C if not analyzed within 4 hours, or freeze specimens at -18 degrees C if analysis is delayed beyond 48 hours. Do not use specimens obtained through catheters used to infuse hyperalimentation fluid. Urine Specimens: Collect specimens by standard laboratory procedure. Keep specimens refrigerated until analysis. Dilute each specimen 40-fold with reagent grade water (1 mL patient plus 19mL of water, then take 1 mL of this dilution & add 1 mL of water) before analysis. Multiply results by 40 to obtain the creatinine value. Dynamic range for urine CREA is 0.1 - 16.5 mg/dL. See creatinine in body fluid Minimum sample size is 0.5 mL; with an optimum size of 1.0 mL or larger.

Related

creatinine creatinine clearance

General

creatinine in serum/plasma/blood renal function tests; renal function panel

References

  1. Kodak Ektachem 700 Analyzer Operator's Manual, Kodak Clinical Products, Rochester, New York.
  2. Kodak Ektachem Slide Package Inserts, Kodak Clinical Products Rochester, New York.
  3. Kodak Ektachem Training Manual, Kodak Clinical Products, Rochester, New York.
  4. Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 620.
  5. Medical Knowledge Self Assessment Program (MKSAP) 11, 16, 17, 18. American College of Physicians, Philadelphia 1998, 2012, 2015, 2018.
  6. Clinical Diagnosis & Management by Laboratory Methods, 19th edition, J.B. Henry (ed), W.B. Saunders Co., Philadelphia, PA. 1996, pg 11.
  7. Prescriber's Letter 9(5):28 2002
  8. Creatinine, Serum or Plasma Laboratory Test Directory ARUP: 20025 - Panel of 11 tests Laboratory Test Directory ARUP: 20144 - Panel of 9 tests Laboratory Test Directory ARUP: 20399 - Panel of 15 tests Laboratory Test Directory ARUP: 20408 - Panel of 6 tests Laboratory Test Directory ARUP: 20474 - Creatinine, Serum or Plasma Laboratory Test Directory ARUP: 20725
  9. Loria A et al. Low preoperative serum creatinine is common and associated with poor outcomes after nonemergent inpatient surgery. Ann Surg 2023 Feb; 277:246. PMID: 36448909 https://journals.lww.com/annalsofsurgery/Abstract/2023/02000/Low_Preoperative_Serum_Creatinine_is_Common_and.12.aspx

Component-of

carnitine/creatinine in serum/plasma chemistry 14 panel (comprehensive metabolic panel, CMP, chem 12, SMA12, SMA20) chemistry 7 panel (Chem-7 SMA7) chemistry 8 panel (basic metabolic panel, BMP, basic chemistry panel) chemistry 8 panel with ionized calcium; basic metabolic panel (BMP) with ionized calcium chronic kidney disease epidemiology (CKD-EPI) collaboration equation creatinine clearance cyclic AMP/creatinine in serum/plasma Modification of diet in Renal Disease (MDRD) Study equation parathyroid panel protein/creatinine in serum/plasma