TY - JOUR
T1 - Evaluation of the impact of delayed centrifugation on the diagnostic performance of serum creatinine as a baseline measure of renal function before antiretroviral treatment
AU - Chikomba, Chemedzai E.
AU - Padoa, Carolyn J.
AU - Tanyanyiwa, Donald
N1 - Funding Information:
We received the i-STAT machine and the cartridges from Obsidian Health (Pty) Ltd the official distributor of Abbott Point of Care South Africa. The company did not influence the protocol formulation, recruitment of participants, data analysis or the final write-up.
Publisher Copyright:
© 2020.
PY - 2020
Y1 - 2020
N2 - Background: The measurement of serum creatinine is a standard requirement of the medical management of people living with HIV. Renal dysfunction is common, both as a complication of HIV-infection and as a result of its treatment. The detection of abnormal renal function before the start of antiretroviral therapy will impact patient management and the outcome of treatment. Objectives: This study aimed to determine if a time delay in the centrifugation of serum samples affected the creatinine level and the estimated glomerular filtration rate as recorded on the analytical platforms used in the laboratory. Methods: Twenty-two (n = 22) HIV-positive, newly diagnosed and treatment-naïve patients were randomly recruited from Alexandra Health Clinic, Johannesburg, South Africa. Serum samples were centrifuged at six time intervals following receipt of the sample viz. < 4 h (baseline), 6 h, 24 h, 48 h, 72 h and 96 h. Creatinine concentrations were measured on the Roche platform utilising the enzymatic and kinetic Jaffe methods. Whole blood samples were also analysed with the Abbott i-STAT point-of-care instrument. The estimated glomerular filtration rate was calculated using the Cockcroft Gault, CKD-Epidemiology Collaboration and Modified Diet and Renal Disease v3/4 equations. Results: At baseline (< 4 h) there was good agreement between the enzymatic and kinetic Jaffe methods: bias 1.7 μmol/l. The enzymatic and i-STAT creatinine concentrations were stable over 96 h viz. changes of 1.8% and 5.7%. However, from 24 h onwards agreement between the enzymatic and kinetic Jaffe methods was poor with the latter measuring 43.7 μmol/l higher than the enzymatic method at 96 h. Creatinine concentrations measured with the kinetic Jaffe method increased significantly in samples centrifuged after 6 h (p < 0.001, 61.7% change), and resulted in a 95% decline in eGFR at 96 h as determined with the CKD-Epidemiology Collaboration equation. Conclusion: The analysis of serum creatinine using the isotope dilution mass spectrometry traceable kinetic Jaffe method is unreliable if performed on samples centrifuged ≥ 6 h after collection. The raised creatinine concentration can affect clinical decisions such as renal functional assessment, choice of antiretroviral drug or regimen, and the dose and frequency of medication.
AB - Background: The measurement of serum creatinine is a standard requirement of the medical management of people living with HIV. Renal dysfunction is common, both as a complication of HIV-infection and as a result of its treatment. The detection of abnormal renal function before the start of antiretroviral therapy will impact patient management and the outcome of treatment. Objectives: This study aimed to determine if a time delay in the centrifugation of serum samples affected the creatinine level and the estimated glomerular filtration rate as recorded on the analytical platforms used in the laboratory. Methods: Twenty-two (n = 22) HIV-positive, newly diagnosed and treatment-naïve patients were randomly recruited from Alexandra Health Clinic, Johannesburg, South Africa. Serum samples were centrifuged at six time intervals following receipt of the sample viz. < 4 h (baseline), 6 h, 24 h, 48 h, 72 h and 96 h. Creatinine concentrations were measured on the Roche platform utilising the enzymatic and kinetic Jaffe methods. Whole blood samples were also analysed with the Abbott i-STAT point-of-care instrument. The estimated glomerular filtration rate was calculated using the Cockcroft Gault, CKD-Epidemiology Collaboration and Modified Diet and Renal Disease v3/4 equations. Results: At baseline (< 4 h) there was good agreement between the enzymatic and kinetic Jaffe methods: bias 1.7 μmol/l. The enzymatic and i-STAT creatinine concentrations were stable over 96 h viz. changes of 1.8% and 5.7%. However, from 24 h onwards agreement between the enzymatic and kinetic Jaffe methods was poor with the latter measuring 43.7 μmol/l higher than the enzymatic method at 96 h. Creatinine concentrations measured with the kinetic Jaffe method increased significantly in samples centrifuged after 6 h (p < 0.001, 61.7% change), and resulted in a 95% decline in eGFR at 96 h as determined with the CKD-Epidemiology Collaboration equation. Conclusion: The analysis of serum creatinine using the isotope dilution mass spectrometry traceable kinetic Jaffe method is unreliable if performed on samples centrifuged ≥ 6 h after collection. The raised creatinine concentration can affect clinical decisions such as renal functional assessment, choice of antiretroviral drug or regimen, and the dose and frequency of medication.
KW - Antiretroviral
KW - Estimated GFR
KW - I-STAT
KW - Kidney function
KW - Kinetic Jaffe
KW - ROCHE
KW - Serum creatinine
UR - http://www.scopus.com/inward/record.url?scp=85090343185&partnerID=8YFLogxK
U2 - 10.4102/SAJHIVMED.V21I1.1056
DO - 10.4102/SAJHIVMED.V21I1.1056
M3 - Article
AN - SCOPUS:85090343185
SN - 1608-9693
VL - 21
JO - Southern African Journal of HIV Medicine
JF - Southern African Journal of HIV Medicine
IS - 1
M1 - M1711109
ER -