But the HP employee, based in Houston, also knew that getting a doctor's appointment wasn't going to be easy during her two-week business trip to company headquarters in Palo Alto.
Then, one of her colleagues told her: "Oh no, you don't have to go anywhere; there's a health clinic here on-site."
She waited just 15 minutes before the staff doctor saw her, diagnosed her symptoms as a bacterial infection and prescribed testing, treatment and an X-ray follow-up.
"They even followed up with phone calls to me on both days I was still there, making sure I was alright and did not need anything," she said. The doctor "sent all my information to my primary-care doctor. When I got back to Houston and followed up with him, he had everything he needed."
The clinic that helped Posa out was set up in 2011 on HP's Stanford Research Park campus on Hanover Street to provide health care for the company's 5,000 employees and their families.
Run by Take Care Health Systems, a Walgreens pharmacy subsidiary, the clinic is one of three at HP campuses; the other two are in Plano and Houston. The local clinic provides primary care, first aid, flu shots and physicals, as well as urgent-care services and procedures such as biopsies and joint injections.
The clinic is open to all employees with HP health insurance, according to Dr. Archana Dubey, the Palo Alto site's supervising physician, who is also medical director of all three HP health centers.
On-site clinics have evolved over the past 80 years. Originally offering first aid for workplace injuries, they are now corporate health care hubs aimed at giving employees timely access to medical care during the work day.
Most manufacturing and service-oriented companies have always provided some sort of on-site care. As far back as in the 1930s, Kaiser created health care centers for the railroad camps on the West Coast, said Larry Boress, executive director of the National Association of Worksite Health Centers.
By the 1980s, companies added "holistic wellness" programs offering smoking cessation, nutrition, and stress and weight management, according to the book Worksite Health Promotion.
"Many employers had developed their own centers around the late 1980s to early 1990s, hiring their own people, building their own sites. But they got away from it, mostly because of the economy, concerns about liability, malpractice insurance problems, problems with the local medical communities and a variety of such reasons. It seemed not to take off," Boress said.
Interest in on-site centers is again growing, however, as health care costs rise and physicians become busier, especially when 30 million more people are soon expected to start getting health care access under the federal Affordable Care Act, he added.
Today, an employee can walk into an on-site health center for flu shots, blood tests, vaccinations, physical therapy, acupuncture or chronic disease management. Some centers also have radiology labs, vision care, dental services and a pharmacy on-site, depending on the space available at the company, its number of employees and the costs involved.
Skin and breast cancer screenings, blood drives, "lunch and learn" educational seminars and health workshops are also organized, sometimes in collaboration with local hospitals. More than 300 employees attended a skin cancer screening organized last summer at the HP clinic.
Companies with as few as 200 employees can provide some sort of on-site services, ranging from "having a nurse practitioner coming in for 10 to 20 hours a week to a full-blown, 50,000-square-foot operation," Boress said.
"Sometimes, in a high-rise building, the owner might open up a health center for the offices, just like a gym, so that multiple employers can use it."
There are employers who hire their own medical staff, while many outsource the centers to third-party vendors — such as Take Care Health Systems — in the rapidly growing corporate health care market.
About 1, 200 firms currently operate on-site clinics across the country, a 2009 Fuld & Co. paper estimated.
Cisco's LifeConnections Health Center — also operated by Take Care Health — was one of the first centers in the Bay Area. Facebook, Lockheed Martin, Apple and Google also offer health care clinics.
Inside the colorful and airy Facebook health center in Menlo Park, decorated with a surfing motif, patients are checked in with an iPad at the reception desk. The center — operated by California-based Crossover Health Medical Group — has a small waiting room, two exam rooms, two rooms for acupuncture treatment and a separate room for physical therapy and chiropractic care. Employees have scribbled their feedback on one wall, similar to walls in other buildings on campus.
"We do everything from primary care to women's health, travel care, flu shots, physicals, allergy shots, occupational health, breast cancer awareness, mindfulness seminars and skin cancer screening," said Nina McQueen, director of Global Benefits at Facebook.
Physicians are also on call after working hours for urgent medical needs.
For new employees who don't have enough information about local health care, finding a community physician can be challenging — one of the reasons why the center was opened last fall.
"We realized that a lot of our employees move here and might be coming from universities, off their parents' health plan or from different parts of the country, and they didn't have relationships locally," McQueen said.
About half of Facebook employees have been treated at the health center so far, "which is a really high percentage considering we just started in August," she said. More than 2,000 Facebook employees work on the campus.
Zahan Malkani, a recent Facebook hire and native of India, found it easier to visit the center than go through the unfamiliar route of finding a local physician.
When he recently injured his elbow biking down Bryant Street in Palo Alto, he was treated at the center within an hour — and without an appointment. It would have taken at least two to three days to get an appointment at the Stanford University clinic he went to as a graduate student, he said.
At the Facebook clinic, "they seemed very 'on the ball'. ... I was in and out pretty quickly," he said.
He thinks the clinic would probably be most useful for either urgent care or minor ailments.
"It's the same reason that there's a barber shop on campus — letting you avoid that one-hour detour," he said.
Improving employee productivity by reducing absenteeism is one of the top three reasons employers invest in on-site clinics, a 2012 Towers Watson survey reported. Reducing health care costs and creating an integrative center for wellness programs are the other two reasons.
According to Dubey, employees try to put off doctor's visits until they are very sick in order to avoid missing work.
She helped set up the clinic at HP after having worked previously at Stanford Family Medicine and later at Google's on-site clinic.
The patient outcome at the HP clinic was "phenomenally different and much better" than in a community health setting, she observed, from her experience at both.
"You attend to your medical situation quicker if it's at work, and get your preventative care a lot more proactively," she said.
With employees frequently traveling abroad for work, on-site health centers also focus on prophylactic care and travel-related illness, she added. They offer the appropriate shots before the trip and prompt post-trip care, should the employee have fallen ill while traveling.
Some employers may charge a minimum co-payment for services — between $10 and $30 at the Facebook health center, for instance, according to its website — while some, such as Lockheed Martin in Sunnyvale, charge no fee.
One of 26 countrywide Lockheed Martin centers, the Sunnyvale wellness center has provided first aid for its 6,000 employees for decades. Two years ago, the center was remodeled and additional staff hired to expand the services to urgent care, health coaching and vaccinations.
Lynne McNeil, a recently retired Lockheed Martin employee, found her experience there comparable to that of her regular doctor the times she dropped in, once for a cut in her eye and the other for a mild cold.
"I thought it was super-convenient and a really good thing for employees. ... You don't want to take time out of your work to go to a doctor's clinic for a 15-minute appointment and end up being there for two hours," she said.
Dr. Dan Azar, Lockheed Martin's regional managing physician, said the centers can treat employees the same day or, at latest, the next.
"We have employees who walk in through the door, and we'll see them that hour. We also have more time than some of our peers in private practice to answer questions for employees," he said.
"Maintaining a productive workforce and a high quality of life among its employees" are the reasons the wellness center was set up, he said.
Last year employees visited all 26 Lockheed Martin wellness centers a total of 78,000 times, according to Azar.
While company officials tout the costs they save by providing health care to their workers, limited information is available on how those savings are tracked.
Johns Hopkins researchers who studied a 700-employee workplace in North Carolina found that operating the on-site clinic cost only half of what the company spent when workers got health care off site, a figure that included the loss of productivity.
The actual cost of setting up a health center varies depending on the size, utilization, staffing, hours of operation and types of services, plus other expenses such as malpractice insurance, benefits and vendor fees, Boress said.
Seventy-five percent of operating costs are related to staffing, according to a 2010 Mercer report. Hiring one mid-level practitioner with a receptionist/medical assistant can cost roughly $350,000 per year. Clinics with full-time physicians and additional ancillary services, such as X-rays, a pharmacy, vision care and physical therapy, can cost considerably more.
There are, however, some ways to track both long-term and short-term benefits.
"You could measure whether or not you've reduced the number of people who use hospital emergency rooms, and the cost of that, the percentage of people who get flu shots or biometric screens, the number of people who use the health center as opposed to going outside — you can identify some of those basic cost-savings within 12 months," Boress said.
Dubey acknowledged that all of the above statistics are taken into account — as well as patient waiting times and patient satisfaction surveys conducted via a third party — in the quarterly return-on-investment (ROI) calculations for HP, although the actual methodology and numbers are proprietary information, she said.
"In general, it may take 18 months from the time of setup to reach the 'tipping point,' to see positive results," she said, adding that a company must have at least 1,500 or more employees to get a good return on investment.
The National Association of Worksite Health Centers is looking into developing standard methods to measure on-site centers' performance.
When renewed interest in on-site clinics started to take off, questions arose in the medical field as to how they would affect established local health care providers — and their revenues, Boress said.
But rather than cut-throat competition, longtime medical groups appear to be collaborating with companies and their workplace clinics, at least in the Bay Area.
"In the beginning, there was this impression that we might be stepping on each other's toes," said Dr. Ronesh Sinha, lead physician for Palo Alto Medical Foundation's corporate outreach efforts. "But now we find that health care is so complex, and for a busy employer, we have to figure out ways to partner and make it simple and convenient for the employee.
"Our hope is that it will probably offload our burden, and we'll have more availability and take on more patients," he said.
The medical foundation's involvement with on-site centers has evolved from customized lectures to mobile clinics and other services, he added.
Some hospitals do compete with private vendors to establish their own on-site clinics, but large employers like Cisco or Apple prefer to hire health companies that can easily scale up to provide services nationally, or even worldwide, according to Sinha.
Hospitals and on-site centers, however, work together at times to organize seminars and refer employees to specialists.
A dermatology telehealth program launched by Stanford Hospital & Clinics in collaboration with Cisco, for instance, allows employees to consult with a Stanford dermatologist while in Cisco's Health Center via videoconference. Stanford Hospitals also recently conducted lectures and blood-pressure screenings in May at Qualcomm for more than 200 employees, according to Stanford's Dr. Sumbul Ahmad Desai, associate chief medical officer for strategy and Innovation.
"We have seen no impact on primary care providers. ... Our goal is to facilitate increased collaboration across the health care continuum," she wrote in an email.
Stanford Hospitals also run its own on-site clinic at the Redwood City campus of DreamWorks Animation, operating since September 2012, where about 500 employees get access to a primary care doctor three times a week.
Palo Alto Medical Foundation doctors also provide monthly lunchtime lectures, biometric screenings, health risk assessments and consultations for Marvell Semiconductors employees.
By partnering with on-site clinics, doctors at local hospitals can access health information gathered during a patient's on-site visit or refer the patient to an on-site clinic for follow-up visits, according to Sinha.
"If a PAMF patient has a chronic condition like diabetes, for instance, and we know ... they have to follow up for an exam or a vaccination, we can refer them to the on-site clinic," he said.
Privacy concerns have surfaced as one area of concern to potential patients of on-site clinics. So employers are trying to address privacy by establishing clear boundaries between the clinic and themselves.
"We have some employers who don't even want their names or logos anywhere near the health center; they just have the vendors' logo — like having a McDonalds in your cafeteria — to make sure that people know that this is a third party and they don't have anything to do with it," Boress said. "Employers still get aggregate reports, so they know what's going on, but they never get individual reports."
HP's clinic, for instance, uses separate Internet and phone lines to maintain appropriate boundaries.
When looking to the future of on-site centers, workplace health professionals predict that the service will add to a company's lure in attracting more employees. Conveniences such as letting employees access their own health information in real-time and make appointments on smartphones could add to the allure.
"When people start looking for jobs, they are going to be asking, 'Is there a health center available on site?'" Boress said.
Some employers, like HP, have already extended their services to employees' families, while others plan to.
"It's certainly our hope to do that," Facebook's McQueen said. "Since it is such a tremendously successful program, we would love to offer it to our (employees') families in future."