They did not disclose the size of the transaction.
Reuters reported on Thursday that Cinven would pay 1.7-1.8 billion euros for Synlab, according to three sources familiar with the deal.
The purchase follows Cinven's May acquisition of French medical diagnostics firm Labco (>> LABCO PROMESSES EUR1) for 1.2 billion euros.
Cinven said the combined businesses would benefit from geographical diversification and a trend towards hospital outsourcing of clinical diagnostics to achieve cost savings in health systems.
"The European diagnostics laboratories market is characterised by strong volume growth, coupled with reduced capacity and high barriers to entry," Alex Leslie, Senior Principal at Cinven, said.
Cinven offered a higher price than Novo Nordisk (>> Novo Nordisk A/S), Apax-owned [APAX.UL] Unilabs and EQT, who were runners-up in the auction, a person familiar with the matter said.
The deal values Synlab at roughly 12 times its expected core earnings, in line with the valuation of Europe's bellwether Sonic (>> Sonic Healthcare Limited).
But compared to other recent lab deals, Cinven is paying a significant premium.
The buyout group bought French group Labco at 9 times core earnings and Sonic paid a multiple of 8 for Swiss medical laboratory group Medisupport.
After the divestment of Synlab, BC Partners has three remaining assets in Germany and sees itself as a buyer.
"BC will continue to be on the lookout for acquisition targets in Germany, among others with a focus on healthcare," said Ewald Walgenbach, Managing Partner at BC Partners.
($1 = 0.8927 euros)
(Reporting by Arno Schuetze and Carolyn Cohn; Editing by Georgina Prodhan)
