07.01.2013 Views

Sorted By Test Name - Mayo Medical Laboratories

Sorted By Test Name - Mayo Medical Laboratories

Sorted By Test Name - Mayo Medical Laboratories

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

CSTC<br />

82994<br />

CFPB<br />

9497<br />

Interpretation: Most individuals display optimal response to cyclosporine with trough whole blood<br />

levels 100 ng/mL to 400 ng/mL. Preferred therapeutic ranges may vary by transplant type, protocol, and<br />

comedications. Therapeutic ranges are based on specimens drawn at trough (ie, immediately before the<br />

next scheduled dose). Blood drawn at other times will yield higher results. This test may also be used to<br />

analyze cyclosporine levels 2 hours after dosing (C2 concentrations); trough therapeutic ranges do not<br />

apply to C2 specimens. The assay is specific for cyclosporine; it does not cross-react with cyclosporine<br />

metabolites, sirolimus, sirolimus metabolites, tacrolimus, or tacrolimus metabolites. Results by liquid<br />

chromatography with detection by tandem mass spectrometry (LC-MS/MS) are approximately 30% less<br />

than by immunoassay.<br />

Reference Values:<br />

100-400 ng/mL<br />

Clinical References: 1. Moyer TP, Post GR, Sterioff S, et al: Cyclosporine nephrotoxicity is<br />

minimized by adjusting dosage on the basis of drug concentration in blood. <strong>Mayo</strong> Clin Proc 1988<br />

March;63(3):241-247 2. Kahan BD, Keown P, Levy GA, et al: Therapeutic drug monitoring of<br />

immunosuppressant drugs in clinical practice. Clin Ther 2002 March; 24(3):330-350 3. Dunn CJ,<br />

Wagstaff AJ, Perry CM, et al: Cyclosporin: an updated review of the pharmacokinetic properties, clinical<br />

efficacy, and tolerability of a microemulsion-based formulation (Neoral) 1 in organ transplantation. Drugs<br />

2001;61(13):1957-2016<br />

Cystatin C, Serum<br />

Clinical Information: Cystatin C is a low molecular weight (13,250 kD) cysteine Proteinase inhibitor<br />

that is produced by all nucleated cells and found in body fluids, including serum. Since it is formed at a<br />

constant rate and freely filtered by the kidneys, its serum concentration is inversely correlated with the<br />

glomerular filtration rate (GFR); that is, high values indicate low GFRs while lower values indicate higher<br />

GFRs, similar to creatinine. The renal handling of cystatin C differs from creatinine. While both are freely<br />

filtered by glomeruli, once it is filtered, cystatin C, unlike creatinine, is reabsorbed and metabolized by<br />

proximal renal tubules. Thus, under normal conditions, cystatin C does not enter the final excreted urine<br />

to any significant degree. The serum concentration of cystatin C remains unchanged with infections,<br />

inflammatory or neoplastic states, and is not affected by body mass, diet, or drugs. Thus, cystatin C may<br />

be a more reliable marker of renal function (GFR) than creatinine.<br />

Useful For: As an index of glomerular filtration rate, especially in patients where serum creatinine may<br />

be misleading (eg, very obese, elderly, and malnourished patients) Assessing renal function in patients<br />

suspected of having kidney disease Monitoring treatment response in patients with kidney disease<br />

Interpretation: Elevated levels of cystatin C indicate decreased glomerular filtration rate Due to<br />

immaturity of renal function in neonates, cystatin C levels are higher in those or =23 years: 0.57-1.29 mg/L<br />

Reference values have not been established for patients that are

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!