Table 2.

Required clinical sample size for the various UCP-LF assay formats

Test description	Example assay name CAA antigen assay	Biological matrixa	Sample required (μL)b	Maximum sample input (μL)c
20 μL assay – antigen	SCAA20	serum	50	20
0·5 mL assay – antigen	SCAA500	serum	600	500
4 mL assay – antigen	SCAA4000	serum	5000	4000
20 μL assay – antigen	UCAA10	urine	50	10
0·5 mL assay – antigen	UCAA250	urine	500	250
4 mL assay – antigen	UCAA2000	urine	2500	2000
15 mL assay – antigen	UCAA7500	urine	10000	7500
20 μL assay – antigen	SalCAA15	saliva – Salivette	1 salivette	15
0·5 mL assay – antigen	SalCAA375	saliva – Salivette	1 salivette	375
20 μL assay – antigen	WMSalCAA10	saliva – WMSS	50	10
0·5 mL assay – antigen	WMSalCAA250	saliva – WMSS	500	250
4 mL assay – antigen	WMSalCAA2000	saliva – WMSS	4000	2000

Test description	Example assay name SEA antigen assay	Biological matrix	Sample required (μL)d	Sample input (μL)e
antibody	SAbSEA	serum	1	0·1 through 4
antibody	UAbSEA	urine	1	1 through 20
antibody	SalAbSEA	saliva – Salivette	1 salivette	1 through 20
antibody	WMSalAbSEA	saliva – WMSS	1	1 through 20

^aSerum and urine collection is standardized. Saliva collection, however, is quite variable; different saliva collectors are available (Malamud et al. 2005; Corstjens and Malamud, 2008) and also saliva can be collected from different parts of the mouth. Currently assays are evaluated using either whole mouth-stimulated saliva (clarified by centrifugation) or saliva collected using Salivette collectors (SARSTEDT AG & Co.).

^bThe required sample amount is the volume needed to ensure maximum sample input. The minimum requested sample volume is 50 μL; this allows convenient sample handling (transport and storage) and extraction of the sample with TCA.

^cThe maximum sample input translates to the maximum volume of the biological matrix (relating to the CAA concentration) that is actually used in the assay. Lower amounts are feasible but will affect the lower limit of detection (note: high infection grades may require 10- or 100-fold dilution of the sample). Higher amounts are possible when using the 500, 4000 and 15000 concentration devices; this requires reloading of the devices which can be done multiple times. Note that for urine the actual sample input is only half that of serum; a consequence of the fact that TCA extraction of serum samples generates a large pellet (about 50% of the total volume), whereas urine commonly generates only a small pellet. The composition of saliva is quite variable and TCA extractions in general generate a larger pellet than observed for urine samples, but significantly less than the serum samples.

^dIn the foreseen combined testing approach, supplying 50 μL for the antigen assays would also allow testing for antibodies.

^eFor antibody testing the sample input is flexible, however the volume and dilution will affect the cut-off threshold. Cut-off levels are best determined from a group representing the same ethnicity and geography.