Department of Neurology, Innsbruck Medical University, Innsbruck, Austria.
Clin Chem Lab Med. 2010 Feb;48(2):209-12. doi: 10.1515/CCLM.2010.040.
The cerebrospinal fluid/serum glucose ratio (CSF/S(glu)) and CSF lactate measurements are part of the routine CSF work-up. The in-vitro stability of both metabolites in CSF has not been formally investigated.
Following collection, CSF/S(glu) and CSF L-lactate concentrations were measured repeatedly at five time points (baseline, 1 h, 2 h, 4 h and 24 h) in CSF and whole blood specimens stored at 4 degrees C.
CSF glucose and lactate concentrations were stable over 24 h in samples with both normal and increased CSF cell counts. The CSF cell count did not influence CSF glucose concentrations, but correlated significantly with CSF lactate concentrations. The CSF/S(glu) increased significantly over time due to glucose consumption.
Glucose and L-lactate are stable in CSF specimens at 4 degrees C over 24 h. The CSF/S(glu) seems to be more reliable than CSF lactate because it is independent of the cell count. Falsely increased CSF/S(glu) may be corrected by the rate of consumption of blood glucose.
脑脊液/血清葡萄糖比值（CSF/S(glu))和脑脊液乳酸测量是常规脑脊液检查的一部分。这两种代谢物在脑脊液中的体外稳定性尚未经过正式研究。
采集后，将 CSF/S(glu)和 CSF L-乳酸浓度在 CSF 和全血标本中分别于 4°C 下储存 5 个时间点（基线、1 小时、2 小时、4 小时和 24 小时）进行重复测量。
在正常和增加的 CSF 细胞计数的样本中，CSF 葡萄糖和乳酸浓度在 24 小时内稳定。CSF 细胞计数不影响 CSF 葡萄糖浓度，但与 CSF 乳酸浓度显著相关。由于葡萄糖消耗，CSF/S(glu)随时间显著增加。
在 4°C 下，CSF 标本中的葡萄糖和 L-乳酸在 24 小时内稳定。CSF/S(glu)似乎比 CSF 乳酸更可靠，因为它不受细胞计数的影响。由于血糖消耗，假性增加的 CSF/S(glu)可能会得到纠正。
