Summary of literature search for reference ranges of CSF glucose, CSF/plasma glucose ratio and CSF lactate.

<p>N - number of CSF samples included in study; wk(s) – week(s); dys – days; yrs- years; P – percentile.</p

Flow chart of inclusion of CSF samples.

<p>N – number of CSF samples.</p

Age-specific CSF glucose, CSF/plasma glucose ratio and CSF lactate values.

<p>(A) CSF glucose concentration in 8,871 samples. CSF samples with CSF glucose >10.0 mmol/L (n = 4) are not shown; (B) CSF/plasma glucose in 4,516 samples. CSF samples with CSF/plasma glucose >1.5 (n = 5) are not shown; (C) CSF lactate concentration in 7,614 samples. CSF samples with CSF lactate >5000 µmol/L (n = 22) are not shown. Lines indicate 5^th and 95^th percentile values.</p

Relation between plasma glucose and CSF glucose.

<p>(A) Relation between plasma glucose and CSF/plasma glucose ratio in 4,508 CSF samples. CSF samples with CSF/plasma glucose ratio >1.5 (n = 5) are not shown. (B) Relation between plasma glucose and CSF glucose in 4,513 CSF samples. The grey areas indicates normoglycemia (plasma glucose >3.0 and <7.8 mmol/L).</p

Age-specific reference values for CSF glucose, CSF/plasma glucose ratio and CSF lactate.

<p>Reference values are based on the 5^th to 95^th percentile values. The subgroups from the original data (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0042745#pone.0042745.s001" target="_blank">Tables S1</a>,<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0042745#pone.0042745.s002" target="_blank">S2</a>,<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0042745#pone.0042745.s003" target="_blank">S3</a>) were clustered into age groups which are commonly used in daily clinical practice (as used by MeSH, Pubmed).</p>*<p>Reference range after exclusion of CSF samples of patients with an unknown or abnormal plasma glucose (<3.0 mmol/L or >7.8 mmol/L) at the moment of lumbar puncture (only represented if >10% different from to the original value). Numbers between brackets represent values without correction for plasma glucose. ‡Reference range after exclusion of CSF samples with CSF lactate >3000 µmol/L (only represented if >10% different from the original value). Number between brackets represents upper limit without exclusion of CSF samples with CSF lactate >3000 µmol/L.</p

Intralaboratory lot-to-lot variation.

<p>Results in this graph are based on deming regression and show the CSF levels of lot 1 and lot 3 for Aβ1-42 (A), t-tau (B), and p-tau (C). The slope is different for Aβ1-42 levels between lot 1 and lot 3. The mean difference in CSF levels between lot 1 and 3 was significantly different for Aβ1-42 and t-tau. Lot 1 = clinical routine lot, lot 3 = LeARN lot, Aβ = amyloid beta, t-tau = total tau, p-tau = phosphorylated tau.</p

Change in CSF marker classification according to cut-offs.

<p>Results are CSF levels only for subjects in which reanalysis let to a different biomarker classification using the cut-offs from Amsterdam to define abnormal CSF values. On the left (A) are changes in biomarker levels for intralaboratory reanalysis and on the right (B) for interlaboratory reanalysis. The arrow represents the applied Amsterdam CSF cut-off. Analysis 1 is routine practice and analysis 2 is performed as part of the LeARN study. CSF = cerebrospinal fluid, Aβ = amyloid beta, t-tau = total tau, p-tau = phosphorylated tau.</p

Internal control data of the Amsterdam laboratory.

<p>Results are changes in high and low CSF biomarker levels for intralaboratory reanalysis in two lots (routine lot and LeARN lot) as part of internal control of data at the Amsterdam laboratory. A) Aβ1-42: Lot 1 used from February 2010 to February 2011 (n = 18) and lot 2 used from March to October 2012 (n = 17). B) T-tau: Lot 1 used from February 2010 to April 2011 (n = 24) and lot 2 used from March to June 2012 (n = 11). C) P-tau: Lot 1 used from February 2010 to April 2011 (n = 23) and lot 2 used from March to October 2012 (n = 11). CSF = cerebrospinal fluid, Aβ = amyloid beta, t-tau = total tau, p-tau = phosphorylated tau. *P<0.001 for differences between lot of analysis 1 (routine lot) and lot of analysis 2 (LeARN lot).</p

Bland-Altman plots of variability between CSF analyses.

<p>The average of CSF analysis 1 and 2 is plotted against the difference between both analyses, on the left (A) for CSF intralaboratory analyses and on the right (B) for CSF interlaboratory analyses. The solid line represents the mean and the dotted lines the upper and lower 1.95 SD. CSF = cerebrospinal fluid, Aβ = amyloid beta, t-tau = total tau, p-tau = phosphorylated tau.</p

Agreement between CSF analyses.

<p>Results are Pearson correlation and ICC (95% CI) for intra- and interlaboratory CSF analyses. ICC = Intraclass coefficients, ratio = Aβ1-42/t-tau, CSF = cerebrospinal fluid, Aβ = amyloid beta, t-tau = total tau, p-tau = phosphorylated tau.</p><p>*All p<0.001.</p