(Adds details on Davidson Kempner recommendation, share price, background)

July 10 (Reuters) - Davidson Kempner Capital Management LP said on Friday it considered Thermo Fisher Scientific's current offer to acquire German genetic test maker Qiagen NV to be "inadequate" and would not tender its shares into the offer.

The investment manager, which owns a 3% stake in Qiagen, said Thermo Fisher's offer of 39 euros ($44.07) per share was not adequate and believed the standalone fair value to be about 50 euros per share.

Thermo Fisher agreed in early March to buy Qiagen for $11.5 billion to bolster its health diagnostic business, and asked the company's investors to tender their shares in May.

Qiagen reported a preliminary 18%-19% rise in sales and a 68% rise in earnings per share in the second quarter due to strong demand for its products used in coronavirus testing.

Davidson Kempner said if the German diagnostic company was not in a bid situation and was trading freely, the significant increase in earnings would see the stock price trading well into the mid 40 euros.

Qiagen's shares closed at 39.67 euros on Friday.

Earlier this month, one of Qiagen's top ten shareholders told Reuters the takeover by Thermo Fisher no longer made sense unless the offer was increased substantially as the pandemic had boosted the company's prospects.

Davidson Kempner urged Qiagen's board on Friday to issue an adverse recommendation change. The acceptance period for Thermo Fisher's offer ends on July 27.

Thermo Fisher and Qiagen did not immediately respond to requests for comment. ($1 = 0.8850 euros) (Reporting by Manojna Maddipatla and Dania Nadeem in Bengaluru; Editing by Krishna Chandra Eluri and Shounak Dasgupta)