Question

For the following precision data, calculate the mean, SD,
and CV for each of the two control solutions A and B.

These control solutions were chosen because their con-
centrations were close to medical decision levels (XC) for

glucose: 120 mg/dL for control solution A and 300 mg/dL
for control solution B.

Control solution A was analyzed daily, and the follow-
ing values were obtained:

118, 120, 121, 119, 125, 118, 122, 116, 124, 123, 117,
117, 121, 120, 120, 119, 121, 123, 120, and 122 mg/dL.
Control solution B was analyzed daily and gave the
following results:
295, 308, 296, 298, 304, 294, 308, 310, 296, 300, 295,
303, 305, 300, 308, 297, 297, 305, 292, and 300 mg/dL.
Does the precision exceed the total allowable error
defined by the CLIA?

Answer 1

Mean calentation Control solution A Caro mean value = (118+ 120+121+ng+125+ 118+ 122+116 +124t 123 +177 +117+121+120+120 +119 +12 + 123 + 120 +22) 20 - mean value a 120.3 mg/dL control solution B Mean value (295+308 + 296+298+304+290+308+ 310 +296 +300+295+303+305+300+308 +297 +297 + 30% + 292 + 300 ) - mg lite 20 mean value = 300.55 Sorealeulation contron solution A Formula is, 2.(*;-) 3= V- n-1 cohere se Standard deviation (SD) a na number of observation di = The observed values on each observations Xz mean value.

Now Let us construct the table average 120.3 300.55 Noob Observeel Number of observations Observed values of control-A noin 1 values of control-B x; -x (xi-x) of controla Control B 18 120 I 6.5025 22.0g 11.9025 - N minutoooos 121 llo 125 118 122 116 124 123 117 Į 17 308 395 5.29 3008025 308 0.og 55.5025 296 0.49 20.7025 298 1069 304 294 5029 42.9025 2089 55.5025 310 18.49 89.3025 296 13.60 20.7025 300 7029 003025 295 10.89 30.8025 303 10089 600025 305 0.49 003025 300 OOO 308 ss.5025 12-6025 297 1.69 12.6025 397 Doug 305 19.8025 7. 29 292 Ooog 7301025 300 12089 0.3025 Foral-112.2 1588.05 121 120. ñ -n 120 17 121 18 123 79 120 122 20 so of control A= 30 of contool B2 112.2 = 2.43 588.05 ? 25.56

Co-efficient of variation calculation (ev) SD = ev al mean x 10 o) Control A solation 112.2 eva (121 22 x 100)% = 0.0326 x CV 2 00% 1 120.3 = 0.0326 X 100 z 93.29 Control B solution en z (588.05 pond - 300.55 osx100) = 195.65 7 According to CLTA The allowable error limit forprecision in +6 mg (dh which is maintained for solution -A observations but not maintained in case of solution - B measurements