CSF and serum AFP in patients without gestational or neoplastic AFP-secretion

Baseline serum/cerebrospinal fluid ratio of carcinoembryonic antigen and carbohydrate antigen series biomarkers in non-neoplastic diseases: a cross-sectional study on 224 patients

BACKGROUND

The measurement of carcinoembryonic antigen, carbohydrate antigen series biomarkers in cerebrospinal fluid (CSF), is useful for the diagnosis of brain metastasis and leptomeningeal metastases to a certain extent. Their serum/CSF ratios may be of benefit to earlier diagnosis and treatment. However, the normal reference values of the ratios were not available. Accordingly, in this study we analyzed the serum/CSF ratios of tumor markers levels in non-neoplastic diseases patients for possible normal values.

MATERIAL AND METHODS

We screened our database for paired CSF and serum samples which have been collected by lumbar puncture. 224 pairs of CSF and serum samples were obtained and compared. The 97.5th percentile, maximum value, and their serum/CSF ratios were obtained.

RESULTS

The 97.5th percentile and maximum value of CSF CEA, CA125, CA19-9, CA15-3, CA724, and CYFRA21-1 concentration for overall participants were 0.572 μ/mL, 4.343 μ/mL, 2.872 μ/mL, 2.108 μ/mL, 1.62 μ/mL, and 1.997 μ/mL, respectively. Gender had no significant difference in these CSF biomarkers except CA15-3. The 97.5th percentile serum/CSF ratio of CEA, CA125, CA19-9, CA15-3, CA724, and CYFRA21-1 level were 34.554, 44.772, 51.232, 20.941, 20.737, and 5.389 respectively. The serum/CSF ratios in different age groups were also described.

CONCLUSIONS

Here, serum/CSF ratios of six tumor markers were determined in non-neoplastic diseases. The usefulness of this index for diagnosis, management, and prognostic utility of leptomeningeal metastases must be validated in larger cohort studies over the long term.

Method Validation of Human Chorionic Gonadotropin and α-Fetoprotein in Cerebrospinal Fluid: Aiding the Diagnosis of Intracranial Germ Cell Tumors

BACKGROUND

Our study objective was to validate 2 individual methods to measure α-fetoprotein (AFP) and human chorionic gonadotropin (hCG) in cerebrospinal fluid (CSF) on the Roche cobas® 6000 analyzer. A 3-year retrospective chart review of CSF samples analyzed for AFP and hCG was also conducted.

METHODS

Serum samples with high concentrations of AFP or hCG were added to aliquots of pooled CSF. Precision, linearity, detection limit, recovery, carryover, stability, and interference studies of the AFP and hCG+β assays were performed.

RESULTS

Within-day and day-to-day assay imprecision for AFP and hCG assays were <5% at all concentrations tested. The linear range of the AFP assay was established as 1.0-1100 μg/L, and limit of quantification (LOQ) was <1.0 μg/L. The linear range of the hCG assay was established as 1.0-9500 IU/L and LOQ 0.7 IU/L. There was no demonstrable matrix effect, and neither assay was affected by the presence of hemolysis or xanthochromia. AFP in CSF was stable at room and refrigerated temperatures for up to 48 h at concentrations of 19 and 306 μg/L but increased by 24 h at a concentration of 908 μg/L. AFP in CSF was stable frozen (-20 °C) for up to 7 days. hCG in CSF at all concentrations tested was stable at room, refrigerated, and frozen temperatures for up to 7 days.

CONCLUSIONS

The Roche cobas 6000 AFP and hCG+β assays accurately quantify AFP and hCG in CSF, facilitating rapid and accurate diagnosis as well as monitoring of intracranial germ cell tumors.