After she lost her job as a social worker last year, and her health insurance with it, Vanessa Sheppard chose a risky way to save money:

She stopped buying the disposable test strips she needed to check her blood glucose level.

Once, having not tested herself for days, the Type 2 diabetes patient felt so ill that she could not get out of bed. Her mother, who also has diabetes, came to visit and insisted that she borrow her glucose meter and a test strip. The result: a disturbingly high level exceeding 200.

"You get real worried," said Sheppard, 50, of South Philadelphia, whose doctor had told her to shoot for readings between 90 and 130. "You know you need this to maintain your health."

Underinsured patients who cut back on testing to save money are all too common, diabetes experts say. Low-cost test strips are available, but they can be tough to find on store shelves. For patients who have to prick their finger and test the blood several times a day, the strip costs add up.

As if the cost weren't enough to worry about, some experts contend that the strips are not accurate enough and that many patients don't use them properly.

Skipping tests can be dangerous, said Felicia Opiyo, a nutritionist and health educator at Fairmount Primary Care Center, where Sheppard is among her patients.

"Sometimes, they end up in the emergency room because there's no way to test their blood sugar," said Opiyo, whose clinic is operated by the nonprofit Delaware Valley Community Health Inc.

Why so expensive? Although the strips don't look like much, they contain sophisticated enzymes or chemicals that react with blood in such a way that they can be read by the meter.

Each brand of meter must be used with the corresponding brand of strip. Manufacturers sometimes give away the glucose meters or sell them at low cost in the hope that consumers will stick with their brand of strips. So the business model is sometimes likened to the one involving razors and razor blades, or cell phones and minutes.

A typical strip costs about 11 cents to make, said David Kliff, publisher of the Diabetic Investor newsletter. Administrative and marketing expenses can be an additional 10 cents or so for a big company, he said. So, for a strip that retails for $1, the profit margin approaches 80 percent.

After years of double-digit growth, the home market for strips measured $2.7 billion in 2006, though the rate of increase was projected to slow, according to Frost & Sullivan, a consulting and market-research firm.

Sheppard's doctor told her to test her blood several times a day. But, instead, she did it as little as once every two weeks - borrowing test strips and a glucose meter from her mother or from other relatives and friends with diabetes. Sometimes, she got free strip samples at the Fairmount clinic, on Fairmount Avenue near Broad Street.

After six months without insurance, Sheppard signed up for Health Partners, a Medicaid plan. She now has her own glucose meter, a Contour made by Bayer, and gets strips for a minimal co-pay.

For various Independence Blue Cross plans, co-payments range from $10 to $40 for a box of 100 test strips. Medicare patients pay about $15.50 for 100 strips, less if they use mail-order. Medicare covers 100 test strips every three months for noninsulin users, and 100 strips a month for insulin users - more if the doctor says it is medically necessary.

Besides cost, there is also concern about accuracy and whether the strips are useful in managing the disease.

The Food and Drug Administration requires that for glucose concentrations exceeding 75, 95 percent of test results must fall within plus or minus 20 percent of the actual value. The agency has urged tighter standards, as has the American Diabetes Association, which seeks an eventual window of plus or minus 10 percent.

The International Organization for Standardization is reviewing whether a tougher standard is warranted.

Poor accuracy is often caused by user error, said Raylene Ballard, a senior project officer at ECRI Institute, a nonprofit research firm in Plymouth Meeting. Ways to achieve better results include making sure the strips haven't expired and cleaning the meter properly, she said.

In a September 2008 review of meters and strips, Consumer Report evaluated 13 varieties for accuracy, price and other criteria. Most of the strips cost about $1 apiece, with the highest at $1.30. The lowest was the ReliOn Ultima, sold at Walmart for just 44 cents apiece, with an accuracy rating of "very good."

Another low-cost brand, TRUETrack, sold for 60 cents a strip, but with accuracy rated just "fair."

Some low-cost brands can be purchased through online merchants for even less. For example, strips for the Infinity, by U.S. Diagnostics, have been sold for as little as 34 cents.

There's no question that using the strips is easier than visiting the doctor's office, as patients did decades ago.

The tests are vital for patients, primarily those with Type 1 diabetes, who must determine how much insulin they need. But for Type 2 patients on oral medication, the doses don't change depending on test results. Some studies have questioned whether the home-testing improves patient health.

The problem is that patients have to use their results, said Richard Bergenstal, executive director of the International Diabetes Center at the Park Nicollet health system in Minneapolis.

Too often, patients aren't aware what their target numbers should be, or they don't change their diet or lifestyle in response to the readings, said Bergenstal, president-elect of the American Diabetes Association.

"Testing for the sake of poking your finger isn't going to help anyone," he said.

"The important thing is what you do with the results," agreed Nadine Uplinger, director of the Gutman Diabetes Institute, which is part of the Albert Einstein Healthcare Network.

Sheppard, the South Philadelphia patient, is a disciple of this approach. She now tests her blood regularly and uses the results to make sure her diet is working. She has had no serious complications. Sheppard is grateful for the friends and relatives who shared their meters, but she prefers not to depend on them.

"You're not always in a position to do that," she said.

Contact staff writer Tom Avril at 215-854-2430 or