Electrolytes are one of the most commonly ordered laboratory tests. The
standard 4 tests include:
Sometimes, an expanded panel is ordered which may include:
- BUN (Blood urea nitrogen)
Henry JB. Clinical Diagnosis and Management by Laboratory Methods. Twentieth Edition. WB Saunders. 2001.
Creatinine measurement: state of the art in accuracy and interlaboratory harmonization.
Miller WG, Myers GL, Ashwood ER, Killeen AA, Wang E, Thienpont LM, Siekmann L.
Virginia Commonwealth University, Richmond 23298-0286, USA.
CONTEXT: The National Kidney Disease Education Program recommends calculating glomerular filtration rate from serum creatinine concentration. Accurate creatinine measurements are necessary for this calculation.
OBJECTIVE: To evaluate the state of the art in measuring serum creatinine, as well as the ability of a proficiency testing program to measure bias for individual laboratories and method peer groups.
DESIGN: A fresh-frozen, off-the-clot pooled serum specimen plus 4 conventional specimens were sent to participants in the College of American Pathologists Chemistry Survey for assay of creatinine. Creatinine concentrations were assigned by isotope dilution mass spectrometry reference measurement procedures.
PARTICIPANTS: Clinical laboratories with an acceptable result for all 5 survey specimens (n = 5624).
RESULTS: The fresh frozen serum (FFS) specimen had a creatinine concentration of 0.902 mg/dL (79.7 micromol/L). Mean bias for 50 instrument-method peer groups varied from -0.06 to 0.31 mg/dL (-5.3 to 27.4 micromol/L), with 30 (60%) of 50 peer groups having significant bias (P < .001). The bias variability was related to instrument manufacturer (P < or = .001) rather than method type (P = .02) with 24 (63%) of 38 alkaline picric acid methods and with 6 (50%) of 12 enzymatic methods having significant biases. Two conventional specimens had creatinine concentrations of 0.795 and 2.205 mg/dL (70.3 and 194.9 micromol/L) and had apparent survey biases significantly different (P < .001) from that of the FFS specimen for 34 (68%) and 35 (70%) of 50 peer groups, respectively.
CONCLUSIONS: Thirty of 50 peer groups had significant bias for creatinine. Bias was primarily associated with instrument manufacturer, not with type of method used. Proficiency testing using a commutable specimen measured participant bias versus a reference measurement procedure and provided trueness surveillance of instrument-method peer groups.
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Sternberg S. Diagnostic Surgical Pathology. Fourth Edition. Lipincott Williams and Wilkins 2004.
Robbins Pathologic Basis of Disease. Seventh Edition. WB Saunders 2005.
DeMay RM. The Art and Science of Cytopathology. Volume 1 and 2. ASCP Press. 1996.
Weedon D. Weedon's Skin Pathology Second Edition. Churchill Livingstone. 2002
Fitzpatrick's Dermatology in General Medicine. 5th Edition. McGraw-Hill. 1999.
Weiss SW and Goldblum JR. Enzinger and Weiss's Soft Tissue Tumors. Fourth Edition. Mosby 2001.
Commonly Used Terms
Basic Principles of Disease
Learn the basic disease classifications of cancers, infections, and inflammation
Commonly Used Terms
This is a glossary of terms often found in a pathology report.
Learn how a pathologist makes a diagnosis using a microscope
Surgical Pathology Report
Examine an actual biopsy report to understand what each section means
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How Accurate is My Report?
Pathologists actively oversee every area of the laboratory to ensure your
report is accurate
Recent teaching cases and lectures presented in conferences
Last Updated March 11, 2005
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