  An exact calculation of CaI $\lambda 6439.075$A absorption profiles in the
spectra of optical stars in low-mass X-ray binary systems with black holes (BH
LMXBs) is carried out. We show that the approximation of a real Roche lobe
filling star as disk with uniform local line profile and linear limb darkening
law leads to overestimation of projected equatorial rotational velocity
$V_{rot} \sin i$ and accordingly, underestimation of mass ratio $q=M_x/M_v$.
Refined value of $q$ does not affect the mass of a black hole, but the mass of
an optical star has shrunk $\sim 1.5$ times. We present refined components
masses in low-mass X-ray binaries with black holes. Companion masses in BH
LMXBs are found in the mass range 0.1 - 1.6 $M_{\odot}$ with the peak at $M_v
\simeq 0.35 M_{\odot}$. This finding poses additional problem for the standard
evolutionary scenarios of BH LMXBs formation with a common envelope phase (CE).
We also discuss the implications of these masses into the evolutionary history
of the binary.
