Soil Test and Plant Analysis Lab

LSU Soil Testing and Plant Analysis
Laboratory Analytical Performance

North American Proficiency Test (NAPT) Quarterly Results for last six quarters.

Test Date	Percent Acceptable (%)*
	Soil Analysis	Plant Analysis
3rd Q, 2000 4th Q, 2000 1st Q, 2001 2nd Q, 2001 3rd Q, 2001 4th Q, 2001 1st Q, 2002 2nd Q, 2002 3rd Q, 2002 4th Q, 2002 1st Q, 2003 2nd Q, 2003 3rd Q, 2003 4th Q, 2003 1st Q, 2004 2nd Q, 2004 3rd Q, 2004 4th Q, 2004 1st Q, 2005 2nd Q, 2005 3rd Q, 2005 4th Q, 2005 1st Q, 2006 2nd Q, 2006 3rd Q, 2006 4th Q, 2006 1st Q, 2007 2nd Q, 2007	92 95 94 97 84 97 80 95 100 92 95 94 95 90 90 99 93 92 91 97 95 95 96 99 97 99 95 94	93 100 98 88 90 95 95 95 95 96 100 95 95 90 97 80 85 95 75 100 95 87 100 99 100 100 98 98

* Based on a total of 133 and 42 analysis submitted for each round of proficiency soil and plant samples, respectively. The NAPT program sets 4xMAD (Median Absolute Deviation) as its control limits for each analysis. The common acceptable proficiency level for routine commercial laboratories is 75% on a yearly basis.