Are the DNA results false?

A DNA test has revealed that I am not the father to one of my twins. Is this possible?
Concerned hubby,

Dear concerned hubby,
Twins, two babies produced from one pregnancy result from a woman shedding two eggs which implant in the womb after fertilisation. These are called fraternal twins.
Twins can also result from a fertilised egg breaking up completely forming identical twins. Whereas identical twins will have one father, fraternal twins may in some rare cases have different fathers.
Fraternal twins can result from sperms from two different men (heteropaternal superfecundation) fertilising two different eggs. Also sperms from two different acts of sex from the same man can lead to twins but this may be more difficult to prove through DNA tests.
Usually, ovulation does not take place when a woman is pregnant. Fertilisation takes place in the fallopian tubes but it takes a few days (six-10 days) for the fertilised egg to implant.
Sometimes, before implantation, during the six-day fertility window, another egg may be shed raising a possibility of the two different eggs being fertilised by sperms from different men if a woman has sex with different men.
Also, Sperms can last up to five days in the fallopian tubes and a woman having had sex with different men may have a mixture of sperm from these men in the fallopian tubes awaiting ovulation and fertilisation.
So, MBN laboratories could be telling you the bitter truth which anybody with lots of trust for their spouse may find hard to accept.