Several years ago, Silicon Valley venture capitalists were champing at the bit to support blood-testing startup Theranos, a company that promised a revolutionary technology that would allow hundreds of diagnostic tests to be accurately performed from a single drop of blood.

The highly-secretive company was able to raise hundreds of millions of dollars and garner a valuation of about $9 billion before intense scrutiny showed that Theranos’ experimental product did not live up to the hype. Theranos crashed due to a lack of sound scientific results, although the company has been able to continue to secure some financing to stay afloat. But now other blood-testing companies are hoping their products will fulfill the failed promise of Theranos. Nanalyze put together a list of six companies that have the potential to deliver on blood-testing products and assume the "darling" role Theranos once held with investors.

1. Genalyte

San Diego-based Genalyte has developed the Maverick Detection System. That blood-testing system, Nanalyze reported citing company documents, uses silicon photonic biosensors to perform multiple tests off a single drop of whole blood in about 15 minutes. Genalyte has raised about $91.8 million to support its product development. The company planned to unveil the Maverick Detection System at this week’s J.P. Morgan Healthcare Conference in San Francisco.

2. Athelas

Bay Area startup Athelas is named for the healing herb in The Lord of the Rings. The company has developed a small piece of tech that can run a blood-cell count from a drop of blood. As Athelas has been developing its tech, the company has used machine learning to teach its system the difference between different types of blood cells in order to provide greater precision in blood testing. The device, which is being developed for at-home use, is reportedly capable of testing for illnesses that range from the flu to cancer. Nanalyze said the Athelas device is being used for cancer patients to monitor white blood cell counts for chemotherapy. Athelas has raised just under $4 million.

3. Karius

Another Bay Area company, Karius has raised $55 million to support development of its tech. The Karius system requires a full blood-draw but is capable of detecting more than 1,000 infectious diseases by analyzing DNA fragments found in the blood, Nanalyze said. The company’s tech is still in the testing phase.

4. Day Zero Diagnostics

Massachusetts-based Day Zero Diagnostics has raised about $3 million in seed funding to support development of its rapid, whole genome sequencing-based diagnostic, Nanalyze said. The tech is being developed to identify the strain and antibiotic resistance profile of a bacterial infection from a blood draw.

5. Orphidia

San Francisco-based Orphidia is also developing portable blood-testing tech that uses a single drop of blood. Nanalyze noted that Orphidia’s tech can run 40 common diagnostic tests and have results within 20 minutes. That company, which was originally launched in London before moving to the Bay Area, has raised about $2 million.

6. NOWDiagnostics

With $11 million in funding, Arkansas-based NOWDiagnostics already has one approved device in the United States, a pregnancy test. That blood assay test is more accurate than urine tests and provides reliable results without the need for a lab, Nanalyze said. The company also has blood tests available in Europe for cardiac and toxicology concerns. Additionally, NOWDiagnostics is developing blood tests for sexually transmitted disease, food intolerance and common infection diseases such as pink eye.