Good day, and welcome to the Nephros, Inc. Second Quarter 2021 Financial Results Conference Call. [Operator Instructions]. Please note, today's event is being recorded. I would now like to turn the conference over to Kirin Smith, Investor Relations. Please go ahead.

Good afternoon, everyone. This is Kirin Smith with PCG Advisory. Thank you all for participating in Nephros' Second Quarter 2021 Conference Call. Before we begin, I would like to caution that comments made during this conference call by management will contain forward-looking statements regarding the operations and future results of Nephros. I encourage you to review Nephros' filings with the Securities and Exchange Commission, including, without limitation, the company's Forms 10-K and 10-Q, which identify specific factors that may cause actual results or events to differ materially from those described in the forward-looking statements. Factors that may affect the company's results include, but are not limited to, its ability to successfully, timely and cost effectively develop, seek and obtain regulatory clearance for its products and services offerings; the rate of adoption of its products and services by hospitals and other health care providers; the success of its commercialization efforts and its effect on the business of existing and new regulatory requirements and other economic and competitive factors. The content of this conference call contains time-sensitive information that is accurate only as of the date of the live call today, August 5, 2021. The company undertakes no obligation to revise or update any statements to reflect events or circumstances after the date of this conference call, except as required by law. I would now like to turn the call over to Nephros' Chief Executive Officer, Andy Astor. Andy, please go ahead.

Thank you, Kirin. Good afternoon, everyone. I am very pleased to report that Nephros had a solid second quarter, continuing our trend of year-over-year growth. Indeed, our second -- excuse me, our total second quarter net revenue was 44% higher than last year and perhaps more important, total first half revenue was 20% higher than in any previous first half in the company's history. In other highlights, our Pathogen Detection business demonstrated some early success in the field, delivering products and services to end customers. We also acquired GenArraytion, Inc. in an all-stock deal, and we submitted a traditional application for the 510(k) clearance of our HDF product to the FDA. I will be expanding on each of these points shortly, but suffice it to say that it's been a busy quarter for Nephros. Looking forward, our outlook for the second half of the year continues to be optimistic, although with some caution, while we're seeing positive momentum in all of our core markets, it is uncertain whether the COVID-19 Delta variant or future variants may exert downward market pressure in the coming weeks and months. We can only hope that more people will get vaccinated so that we can all put this pandemic behind us. In the meantime, we remain focused on the long term, serving as a resource to our partners and our customers in support of their water management program needs. Now let's look more closely at each of our business segments. Our core Water Filtration business continued to grow in the second quarter. Net filtration revenue was up 40% over the same period of the prior year. Installed base sites, the source of our recurring revenue, were stable. New site sales were within normal limits, and our retention rates were at or above 90%. Our emergency…

[Operator Instructions]. Today's first question comes from Marc Wiesenberger with B. Riley.

Andy, can you explain a little bit more about the dynamics of the emergency response business? And from your perspective, why has that part of the business been slower to rebound? Is it just that Legionella outbreaks aren't happening? And if that's not the case, why do you -- what do you think the impetus is for kind of more normalization?

Well, Marc, nice to hear your voice. And the emergency response business dynamics are very dynamic. And actually, they have rebounded from 2020. We did more in the first quarter, and I'm not sure if that's true in Q2, than we did in all of 2020. So they have rebounded because we believe that testing and frankly, the attention is being paid to diseases other than COVID now that COVID is hopefully on the wane. So it has rebounded, and I think that as long as COVID and, particularly now in the second and third quarter, as the Delta variant is extending and the trends of COVID are rising again, it doesn't surprise me at all that the emergency response business is down a bit. But the truth is if you grass it, if you grass the business, it just looks like a folded piece of paper, it goes up and then down and then up and then down. And it is -- it depends enormously on the size of outbreaks and the size of the hospitals in which the outbreaks occur, and it's just a naturally irregular flow. So that was a long-winded answer. But in summary, it is coming back. I think it will come back inversely in somewhat inverse relationship with COVID's reduction. And I think you will continue -- we will all continue to see it being a regularly irregular business pattern.

Got it. Okay. Moving on, I know you guys provide filters for use in dialysis clinics, but there's a big push to move towards in-home dialysis. And I'm wondering if you could talk about your involvement in that market and maybe expectations for growth opportunities going forward.

Sure. Thanks, Marc. There are several in-home and portable dialysis manufacturers. And we are actually the -- of the filter, the original equipment manufacturer of filters in some of them. That business is strong. It has grown well. We don't disclose the individual numbers, but the dialysis business has been an important part of our continued growth, and we think it will continue to be so. It at least keeps up with our growth in our hospital business and frankly, has exceeded that growth in several of the last few quarters.

Got it. Okay. And then last one for me. Could you just kind of talk about the impetus behind the GenArraytion deal and the potential impacts on the gross margin for the PDS segment going forward?

Sure, sure. Thank you, Marc. The impetus for the deal was pretty much a vertical integration play. We have been buying from GenArraytion for a couple of years several of our assays. At the beginning, it was quite a few. And then as we've developed our own, it was less. But GenArraytion has literally hundreds of assays that they've developed as well as proprietary processes and purchasing them reduces the cost of our development and reduces our time to market. And so I think that it will have a -- I was going to say positive but I'll just say good impact on our gross margin -- on our abilities and gross margins because we're manufacturing now all of our own assays rather than paying wholesale for some of them.

[Operator Instructions]. And ladies and gentlemen, this concludes our question-and-answer session. I'd like to turn the conference back over to Andy Astor for any closing remarks.

All right. Well, it was -- I see all the names up on the screen. It was good to see the several dozen of you that are on the call, and I look forward to seeing you all in the future. I hope you have a great rest of your summer, and we'll talk to you in November.

Thank you, sir. This concludes today's conference call. We thank you all for attending today's presentation. You may now disconnect your lines, and have a wonderful day.