Performance of three cognitive screening tools in a sample of older New Zealanders.

BACKGROUND: With the ubiquitous Mini-Mental State Exam now under copyright, attention is turning to alternative cognitive screening tests. The aim of the present study was to investigate three common cognitive screening tools: the Montreal Cognitive Assessment (MoCA), the Rowland Universal Dementia Assessment Scale (RUDAS), and the recently revised Addenbrooke's Cognitive Assessment Version III (ACE-III). METHODS: The ACE-III, MoCA and RUDAS were administered in random order to a sample of 37 participants with diagnosed mild dementia and 47 comparison participants without dementia. The diagnostic accuracy of the three tests was assessed. RESULTS: All the tests showed good overall accuracy as assessed by area under the ROC Curve, 0.89 (95% CI = 0.80-0.95) for the ACE-III, 0.84 (0.75-0.91) for the MoCA, and 0.86 (0.77-0.93) for RUDAS. The three tests were strongly correlated: r(84) = 0.85 (0.78-0.90) between the ACE-III and MoCA, 0.70 (0.57-0.80) between the ACE-III and RUDAS; and 0.65 (0.50-0.76) between the MoCA and RUDAS. The data derived optimal cut-off points for were lower than the published recommendations for the ACE-III (optimal cut-point ≤76, sensitivity = 81.1%, specificity = 85.1%) and the MoCA (≤20, sensitivity = 78.4%, specificity = 83.0%), but similar for the RUDAS (≤22, sensitivity = 78.4%, specificity = 85.1%). CONCLUSIONS: All three tools discriminated well overall between cases of mild dementia and controls. To inform interpretation of these tests in clinical settings, it would be useful for future research to address more inclusive and potentially age-stratified local norms.

Interference with carcinoembryonic antigen radioimmunoassays by glycosaminoglycans, and their removal.

Using the reagents from the CEA-Roche kit, we found that solutions containing only glycosaminoglycans (GAG) yielded false concentrations of carcinoembryonic antigen (CEA), and mixtures of CEA and GAG produced falsely high values. On the other hand, solutions of GAG yielded no additional CEA concentration when reagents from the Abbott CEA kit were used; rather, the CEA result was decreased with the Abbott kit for a CEA solution also containing GAG. These effects of GAG were not ascribable to contamination, because neither gel filtration nor ion-exchange column chromatography separated the false Roche CEA content related to GAG from their peaks of uronic acid or from their anticoagulant activity. In addition, an enzyme specific for GAG eliminated these GAG-derived false concentrations. Both the positive and negative effects are correlated with concentrations of GAG. We found that the concentration of GAG could be decreased in a solution containing plasma proteins by either heating (70 degrees C, 15 min) or treating with perchloric acid (0.6 mol/L). The former is superior because essentially all GAG added to a solution containing plasma proteins were removed by heat, whereas as much as 25% to 80% of the GAG still remained after acid treatment. The effect of GAG was also completely eliminated by treating the specimens with chondroitinase ABC lyase (EC 4.2.2.4).