Sample application technique affecting whole blood creatinine point of care test stick results.
Author(s): Thurlow V, Egwim I, Hobart C, Vincent R
Publication: Ann Clin Biochem, 2019, Vol. , Page 4563219843569
PubMed ID: 31003580 PubMed Review Paper? No
Purpose of Paper
This paper investigated the effects of different methods of applying blood to test strips on the determination of creatinine levels in blood measured on a point-of-care device and compared the results with those obtained from serum using an autoanalyzer in the laboratory.
Conclusion of Paper
The closest agreement in creatinine values between blood using the point- of -care device and serum values using an autoanalyzer in the laboratory were observed when the test strip was dipped directly into the blood aliquot. Significantly higher creatinine levels were found using the meter when blood was applied to the test strips sideways through a capillary tube or by sampling from a drop of blood than when measured using the analyzer in the laboratory. However, the highest coefficient of variance (CV) for the meter was observed when the test strip was dipped directly into the blood.
Studies
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Study Purpose
This study investigated the effects of different methods of applying blood to test strips on the determination of creatinine levels in blood measured on a point-of-care device and compared the results with those obtained from serum using an autoanalyzer in the laboratory. Paired blood and serum were obtained from 15 patients (details not specified). Blood was applied to test strips by: (1) dipping the test strip directly into the blood aliquot, (2) sideways application to the test strip using a capillary tube, and (3) by sampling from a bead of blood on a glass slide. Test strips were then analyzed in duplicate using the StatSensor-iv point-of-care analyzer. Creatinine levels were measured in duplicate in serum in the laboratory using the kinetic Jaffe method on a Roche Cobas autoanalyzer.
Summary of Findings:
The closest agreement in creatinine values between blood using the point-of-care device (130 µmol/L) and serum using the autoanalyzer in laboratory (140 µmol/L) were observed when the test strip was dipped directly into the blood aliquot. Significantly higher creatinine levels were found using the meter when blood was applied to the test strip sideways through a capillary tube or by sampling from a drop of blood than when measured using the analyzer in the laboratory (153 µmol/L and 158 µmol/L, respectively versus 140 µmol/L). However, the highest coefficient of variance (CV) for the meter was observed when the test strip was dipped directly into the blood (12.8%) rather than applied sideways to the test strip (10.1%) or by sampling from a blood drop (6.1%).
Biospecimens
Preservative Types
- None (Fresh)
Diagnoses:
- Not specified
Platform:
Analyte Technology Platform Small molecule Clinical chemistry/auto analyzer Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Biospecimen Aliquots and Components Blood and blood products Serum
Whole blood
Clinical chemistry/auto analyzer Specific Technology platform StatSensor-iv
Roche Cobas
Clinical chemistry/auto analyzer Specific Detection method Test strip dipped directly into the blood aliquot
Blood applied to the test strip sideways using a capillary tube
Testing from bead of blood on a glass slide