Table 2. Dependencies between predictive values and prevalence.

Prevalence	Very high Test Efficiency		Moderate Test Efficiency
	Sensitivity and Specificity = 0.95, PLR = 19		Sensitivity and Specificity = 0.7, PLR = 2.3
	PPV	NPV	PPV	NPV
90%	99.4%	67.9%	95.5%	21%
50%	95.0%	95.0%	70%	70%
10%	67.9%	99.4%	21%	95%
1%	16.1%	> 99.9%	2.3%	99.6%
0.1%	1.9%	100%	0.2%	> 99.9%
0.01%	< 0.2%	100%	< 0.1%	100%

based on Mühlhauser and Höldke 1999; Bender, 2001; Grimes and Schulz, 2005