Table 2.

CSF biomarker concentrations for protocol 3 (freezing temperature and delay) and 4 (freeze–thaw cycles).a

Protocol1–42, pg/mLP vs standard procedureT-tau, pg/mLP vs standard procedureP-tau181P, pg/mLP vs standard procedure
Protocol 3: freezing temperature and delay (n = 22)
    −80°Cb300 (165–579)359 (46–1875)53 (14–172)
    −20°C313 (166–636)0.135348 (52–1550)0.01252 (10–165)0.005
    Liquid N2335 (172–594)0.048396 (63–1604)0.40555 (10–173)0.068
    24 h at 2–8°C307 (145–576)0.624386 (52–1890)0.29650 (7–169)0.016
    24 h at room temperature324 (178–612)0.065403 (48–1871)0.73255 (10–171)0.625
    48 h at room temperature320 (195–558)0.009384 (50–1919)0.80454 (8–169)0.180
Protocol 4: freeze–thaw cycles (n = 20)
    1 freeze–thaw cycleb428 (190–837)417 (89–2063)48 (14–162)
    2 freeze-thaw cycles443 (229–892)0.667422 (90–2228)0.13347 (14–155)0.742
    3 freeze-thaw cycles411 (229–939)0.783413 (86–1928)0.67249 (14–171)0.245
    4 freeze-thaw cycles398 (178–833)0.022406 (80–2070)0.49150 (15–162)0.749
  • a Data are medians (range). Significant differences are indicated in bold. See also Figure 2.

  • b Standard procedure.