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Value Qualifier Codes

# National Water Information System
# 2024/07/22
# Date Retrieved: USGS Water Data for the Nation Help System
val_qual_cd	val_qual_nm
1s	62s
$	incorrect sample container
&	biological organism estimated as dominant
(	blank greater than the sample-specific Critical Level
)	sample-specific MDC (ssMDC) above contractual MDC
*	sample was warm when received
+	improper preservation
/	matrix spike (MS) recovery outside of acceptable range
=	negative result may indicate potential negative bias
@	holding time exceeded
a	value extrapolated at high end
b	value extrapolated at low end
c	see result laboratory comment
d	sample was diluted
e	see result field comment
f	sample field preparation problem
g	count less than 0.5 percent
h	compound identification verified by alternate method
i	result may be affected by interference
j	count greater than or equal to 15 percent (dominant)
k	counts outside acceptable range
l	sample preparation problem
m	value is highly variable by this method
n	below the reporting level but at or above the detection level
o	result determined by alternate method
p	value reported is preferred
q	insufficient sample received
r	value verified by rerun, same method
s	instrument sensitivity problem
t	below the detection level
u	value reported not confirmable, interference
v	analyte detected in laboratory blank
w	high variability, questionable precision and accuracy
x	interference from sample matrix
y	sample variability described in comment
z	value verified by rerun, alternate method
\	lab control sample (LCS) recovery outside of range or criteria
^	yield outside of contractually acceptable range
~	duplicates do not check (not within the acceptance limits)