To reduce the level of contamination by bacterial products, ultrafiltration systems have been introduced and validated for their capacity to block the passage of bacterial components reactive to the limulus amoebocyte lysate (LAL) test. In this study, the absorptive capacity of polysulfone membranes undergoing disinfection cycles with free chlorine and peracetic acid were evaluated at various concentrations and contact times. The results of this study implicate a relevant physicochemical derangement of the polysulfone membranes treated with sodium hypochlorite but not with peracetic acid, diluted peracetic acid (Dialox) or Amuchina. The implications for the practical use of ultrafilters are discussed.

Disinfectants↗

PubMedDate not supplied

Comparison of immunoassays for tumor markers CA 19-9, CA 15-3 and CA 125: data from an international quality assessment scheme.

Data collected in the 1993 and 1994 cycles of an international external quality assessment (EQA) program and in a national multicenter collaborative study were cumulatively analyzed to evaluate the standardization of the methods currently in use for the assay of mucinous tumor markers CA 19-9, CA 15-3 and CA 125. On average the between-laboratory variability was 15.2 and 16.0 CV% for CA 15-3 and CA 125 respectively; the between-laboratory variability found for CA 19-9 was markedly worse (mean 28.3 CV%). The variability component attributable to systematic differences between different methods/kits was relatively small for CA 15-3 and CA 125 (18% and 24% of the total variability) but markedly larger for CA 19-9 (48% of the total variability). The agreement of CA 19-9 results worsened in the last few years when new nonisotopic techniques became available. The precision of the methods/kits most used in the survey ranged from 9.9 to 13.3 CV% for CA 125 and from 11.6 to 13.9 CV% for CA 15-3. For these two tumor markers the precision of the traditional IRMAs does not appear different from that of the new fully automated nonisotopic techniques. The precision of CA 19-9 methods was on average worse (from 11.7 to 19.6 CV%) although two automated systems exhibited a precision better than that of IRMAs. In conclusion, the results of this study indicate that CA 15-3 and CA 125 are satisfactorily assayed whereas CA 19-9 assay appears affected by larger differences between methods and by poorer precision of laboratories and kits.

Antigens, Tumor-Associated, Carbohydrate↗

PubMedDate not supplied

Predicting prostate biopsy outcome by findings at digital rectal examination, transrectal ultrasonography, PSA, PSA density and free-to-total PSA ratio in a population-based screening setting.

The study offers a retrospective analysis of the positive predictive value (PPV) of several variables, i.e. digital rectal examination (DRE), transrectal ultrasonography (TRUS), PSA value, PSA density (PSAD), and free/total PSA ratio (F/T), for the histologic outcome of 179 prostate biopsies performed within a population-based screening trial. The ratio of spared benign biopsies to missed cancers (SBB/MC) if biopsy results had been decided on the basis of single variables was also evaluated. PPV was 82.9% for DRE, 56.3% for TRUS, 26.6% for PSA (cutoff > or =4 ng/mL), 47.4% for PSA (cutoff > or =10 ng/mL), 42.0% for PSAD (cutoff 0.15), 59.2% for PSAD (cutoff 0.20), 34.9% for F/T (cutoff 0.20) and 40.0% for F/T (cutoff 0.15). SBB/MC was 121/23 for DRE, 96/12 for TRUS, 11/10 for PSA (cutoff > or =4 ng/mL), 107/34 for PSA (cutoff > or =10 ng/mL), 87/23 for PSAD (cutoff 0.15), 109/26 for PSAD (cutoff 0.20), 45/8 for F/T (cutoff 0.20) and 70/14 for F/T (cutoff 0.15). Multivariate analysis of the association with biopsy outcome showed the highest odds ratio for TRUS (13.24, 95% CI=4.4-30.7), and considerably lower values for DRE (4.17, 95% CI=2.0-8-9), PSAD (cutoff 0.20: 3.24, 95% CI=-1.8-5.7) and F/T (cutoff <0.15: 3.16, 95% CI=1.7-1.8). None of the possible variable combinations was clinically useful: the highest PPV (83.3%) was obtained with a combination of suspicious DRE/TRUS, PSAD >0.20 and F/T <0.15, which nevertheless missed 20 of 52 cancers.

Biopsy↗

PubMedDate not supplied

Analysis of PSA velocity in 1666 healthy subjects undergoing total PSA determination at two consecutive screening rounds.

The study purpose was to assess PSA velocity (PSAV) in healthy subjects in order to establish a reliable cutoff for the differential diagnosis of prostate cancer in a screening setting. We studied a series of 1666 healthy men aged 55 to 74 years undergoing two total PSA determinations at a four-year interval within a population-based randomized screening trial at the Centro per lo Studio e la Prevenzione Oncologica of Florence. First and second screening round PSA assays (PSA1 and PSA2) were carried out with the same method and by the same laboratory. PSAV (PSA1-PSA2/year) was determined in non-cancer subjects in the overall series or in specific age and PSA subgroups, and in subjects with cancer detected at the second screening round. Average PSAV in 1648 non-cancer subjects was 0.07 ng/mL/year (range -2.18+5.99, 95% CI 0.05-0.09); at least one third of subjects showed a decrease in PSA (negative PSAV), mostly of limited magnitude and in the low PSA range. Average PSAV in the 18 cancer patients was 1.16 ng/mL/year (range 0.10-5.6, 95% CI 0.56-1.77), which is significantly higher (p<0.01) than in non-cancer subjects. None of the cancer patients showed a PSA decrease over time. Whatever cutoff was taken for PSAV, its power to discriminate cancer was limited: in particular the previously used PSAV cutoff of 0.75 ng/mL/year would have included only 42 of the 1648 non-cancer subjects (specificity 97.5%) but excluded eight of the 18 cancer patients (sensitivity 55.5%). At best, with the adopted screening protocol PSAV (cutoff 0.10 ng/mL/year) could have spared 27.9% of non-cancer subjects with PSA > or =2.5 ng/mL further diagnostic assessment and 22.7% of non-cancer subjects with PSA > or =4 ng/mL random sextant biopsy, while missing no cancers. This study provides a reliable estimate of PSAV based on a large unbiased population sample. PSAV is widely variable over time, particularly at low PSA values. PSAV might be of value as an indicator for diagnostic assessment and random sextant biopsy in a screening setting.

Aged↗