Sometimes examiners and applicants become locked in an argument that is really a side-show. But since it is the Examiner’s (USPTO’s) initial burden to establish grounds of rejection, applicants can be led to believe that their only job is to show an error in the examiner’s rejection. And there is much support in administrative law principles to confirm such a belief by an applicant. But as can be seen in many PTAB decisions, the Board can take a loose interpretation of an examiner’s rejection and affirm on what seems like new reasoning without designating new grounds. Applicants should therefore be prepared to not just show errors in the rejection, but to double check that the examiner did not miss some clear evidence in the record that supports one position or another before appealing.

US 15/429,583 is an illustrative example. The applicant, FRESENIUS, represented by sophisticated patent counsel, appealed a rejection of their application related to a method of detecting the concentration of a substance (e.g., sodium or hydrogen) in a medical fluid (e.g., blood or dialysate) using nuclear magnetic resonance (NMR). Claim 1 on appeal is listed below:

1. A method comprising:

measuring a quantity of a first substance in a reference fluid in a reference fluid cartridge using a nuclear magnetic resonance sensor assembly;
measuring, using the nuclear magnetic resonance sensor assembly, a quantity of a second substance in the reference fluid in the reference fluid cartridge;
measuring, using the nuclear magnetic resonance sensor assembly, a quantity of the first substance in a medical fluid in a medical fluid cartridge;
measuring, using the nuclear magnetic resonance sensor assembly, a quantity of the second substance in the medical fluid in the medical fluid cartridge; and
determining a concentration of the second substance in the medical fluid based on the measured quantities of the first and second substances in the reference fluid and the medical fluid, wherein the first substance is different from the second substance, and wherein the concentration of the first substance in the reference fluid is known.

The examiner rejected the claim as anticipated and obvious over a relatively old reference - Rapaport (US 4,875,486). Rapaport disclosed a similar approach that used the concentration peak level of water relative to that of a standard sample to make estimates about glucose plasma levels. The applicant argued that Rapaport used the peak levels, not the concentration, to make the inference whereas the claim required using concentrations of what would be the water in Rapaort. While technically correct, the Board nevertheless affirmed the rejection by citing to FIG. 5A of Rapaport and proposing an argument that had never been raised by the examiner.

Rapoport discloses that the NMR analysis of the standard sample and the patient sample include peak height data (col. 7, ll. 1–5; col. 8, ll. 1–34; Fig. 5a). As shown in Rapoport’s Figure 5a, the NMR spectrum includes peaks for H2O and glucose. The x-axis for each of these peaks is labelled as “PPM” or parts per million (Rapoport, Fig. 5a). We find that parts per million is a measure of concentration. Rapoport’s equation that is used to calculate the patient’s glucose concentration is based on using the standard solution’s known glucose concentration (K) multiplied by the ratio of water peak heights in the standard sample and patient sample and the ratio of glucose peak heights in the standard sample and patient sample (col. 7, ll. 6–68; col. 8, ll. 1–8).

Despite the examiner never relying on the PPM concentration illustrated in FIG. 5A, and in fact never even citing FIG. 5A throughout prosecution, the board found that Rapaport’s water standard peak height includes within it an indication of the concentration of water in the standard sample and thus was covered by the claim limitation at issue. In other words, since the peak of water was at a specific concentration, even though the calculation did not use that concentration, a concentration was nevertheless determined in a broad sense.

So, an applicant must be careful to consider ways in which the board may consider new reasoning and look outside the specific areas of a reference cited by the examiner in order to affirm the rejection. In this regard, adding and arguing dependent claims that further differentiate a reference or an examiner’s particularly broad interpretation (as discussed in a recent post here) can be helpful as a backstop to avoid a complete affirmance. While prosecution can continue after an affirmance, some examiners are even more entrenched and thus prosecution can become even more drawn out and costly.