Comparison of the cobas Human Immunodeficiency Virus 1 (HIV-1) Test Using the cobas 4800 System With COBAS AmpliPrep/COBAS TaqMan HIV-1 Test and Abbott RealTime HIV-1 Assay and Performance Evaluation of cobas HIV-1.

OBJECTIVES: To compare quantified human immunodeficiency virus type 1 (HIV-1) viral load quantified using the cobas HIV-1 test with that obtained using the CAP/CTM HIV-1 and Abbott RealTime HIV-1 tests and evaluate the performance of cobas HIV-1 using the cobas 4800 system. METHODS: Clinical samples (n = 123) were quantitatively analyzed using the CAP/CTM HIV-1, Abbott RealTime HIV-1, and cobas HIV-1 tests, and the precision, linearity, and limit of detection of the cobas HIV-1 test were evaluated. RESULTS: Comparable results were obtained by both methods: ([log CAP/CTM HIV-1 value] = 0.979 * [log cobas HIV-1 test value] + 0.034) and ([log Abbott RealTime HIV-1 value] = 0.985 * [log cobas HIV-1 test value] + 0.027). cobas HIV-1 test results for 89.4% and 93.5% were within 0.5 log10 IU/mL of the CAP/CTM HIV-1 and Abbott RealTime HIV-1 results, respectively. CONCLUSIONS: The cobas HIV-1 test showed good performance, and its results correlated well with those of other two tests.

Progastrin-releasing peptide is a candidate marker for quality control in clinical sample processing and storage.

For clinical epidemiologic and proteomic studies, the control of preanalytic variation, including sample processing and storage, is important. We evaluated the stability of progastrin-releasing peptide (ProGRP) as a marker for the quality control of stored serum and plasma samples. The ProGRP from 23 healthy volunteers was measured serially for 8 hours at room temperature, and the results were validated with clinical samples from the biobank. A significant difference in ΔProGRP was also noted between good-quality (time delay <4 hours before storage) and poor-quality (time delay ≥4 hours before storage) specimens (mean ± SD, 0.17 ± 0.08 vs 0.36 ± 0.14; P < .001; Wilcoxon signed-rank test). With a ΔProGRP cutoff of 0.22, the sensitivity and specificity of detection of the poor-quality samples were 85.7% and 75.0%, respectively, in clinical validations. We demonstrated that ΔProGRP could be used as a marker for quality control in sample processing and storage in biobanks.

Effects of RBC removal and TRIzol of peripheral blood samples on RNA stability.

BACKGROUND: Purification of mRNA from stored specimens is very important because results from RT-PCR and microarray analyses are largely affected by the quality of mRNA. Moreover, many preanalytical factors during collection, processing, and storage may affect mRNA quality and the expression of peripheral blood mononuclear cells (PBMC). In this study, we evaluate the effects of RBC removal techniques and TRIzol on RNA quality in blood samples. METHODS: We obtained EDTA-blood samples from 50 adult volunteers, and made 10 pools of buffy coats for comparison between protocols and also evaluated RNA quality of clinical samples in biobank. Use of TRIzol and RBC removal (RBC lysis or cell separation) were evaluated their effect on the quality of mRNA from the stored blood samples. RESULTS: RNA integrity with TRIzol was significantly better than that without TRIzol (RIN 4.5 vs. 9.2, respectively; P=0.002). The change in RIN of the PBMC separation method was equivalent to that of the RBC lysis method. After 12 months, IL6 mRNA expression from stored clinical samples in cell separation/TRIzol was stable. CONCLUSIONS: The blood samples frozen in TRIzol after RBC removal preserved RNA quality well. PBMC/TRIzol preservation for storage of blood samples could be a simple protocol for rapid, low-cost biobanking.