Table 2. Correlation of CSF RFFIT titres with day of sample collection (post-onset of symptoms).

Day of sample collection	Number of samples	Median (Q3-Q1) Titres in IU/ml	Range (Max-Min) Titres in IU/ml	χ2	p-value	Multiple comparison
1–7 (A)	16	0.468 (6.56–0.14)	30–0.1	13.82	0.001	A vs B (p = 0.014)
8–14 (B)	20	11.25 (60–2.34)	120–0.1			A vs C (p = 0.001)
>14 (C)	14	22.5 (60–6.56)	240–1.875

These 39 laboratory confirmed cases (where the day of CSF sample collection post-onset of symptoms was known) included 37 patients (48 CSF samples) who were positive by CSF RFFIT and 2 patients (2 CSF samples) who were positive by PCR, but negative by CSF RFFIT.