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. Author manuscript; available in PMC: 2021 Mar 23.
Published in final edited form as: J Immunol Methods. 2013 Nov 23;402(1-2):57–70. doi: 10.1016/j.jim.2013.11.011

Fig. 5. Effect of the Choice of Serum Dilution on Determination of GMAb concentration.

Fig. 5.

A. Effect of the Sample Absorbance to that of the Reference Standard Range. Separate series of standard dilutions (1:100, 1:3000, 1:6000, 1:12000) were prepared from serum from 46 autoimmune PAP patients and 32 healthy people and GMAb concentration was measured for each dilution (184 for autoimmune PAP and 128 for healthy controls) using the GMAb ELISA. Individual measurements were defined as ‘in-range’ if the optical absorbance for the dilution was within the range of the optical absorbance values for the reference standards, ‘low’ (and out of range) if the optical absorbance was less than that of the lowest reference standard, and ‘high’ (and out of range) if the optical absorbance was greater than that of the highest reference standard. Only ‘in-range’ values were used to calculate the mean GMAb concentration. In healthy people, the percent deviation for ‘in range’ values was small (*) and no measurements were greater than the highest reference standard (**). Bars represent the mean (±SD) and the number of determinations is shown above the error bars.

B. Effect of Serum Dilution Factor on Percent Deviation. Data are derived from the experiments shown in panel A but shown here as function of the specimen dilution. In healthy people, the percent deviation for ‘in-range’ values was small at the 1:100 dilution (*) and no determinations were in-range at higher dilutions (**). Bars represent the mean (±SD) and the number of determinations is shown above the error bars.

C. Effect of Serum Dilution on the Frequency of Obtaining ‘In range’ Measurements. Data are derived from the experiments shown in panels A and B. The percentage of determinations that are ‘in-range’ for each of the standard dilutions (1:100, 1:3000, 1:6000, and 1:12000) is shown (bars). Gray bar represent measurements that were ‘in-range’ and the clear bar represents measurements in which GMAbs were undetectable. The cumulative percent of determinations that are ‘in-range’ at each successively greater dilution is shown (open symbols). In healthy people, GMAb values below the LLOQ were accepted as normal and counted as being in-range.