Some of the secondary reasons to perform testing include: to screen for hepatitis B infection in at-risk populations or in blood donors, to determine if someone is a carrier, to detect previous infection (with subsequent immunity), and to determine if immunity has developed due to vaccination.
Abdominal muscle spasm, also known as abdominal rigidity, is a powerful, involuntary contraction of the muscles of the abdomen.During a spasm, the muscle will feel stiff and tender if you apply pressure.ike any other muscles in the body, your abdominal muscles can have spasms that occur as a result of muscle strain during heavy use or overuse, fatigue, dehydration, and alcohol or drug use.
Causes of Muscle Spasms. Muscle spasms in the back can often be caused by a twisting or strain on one of the back muscles, which in turn causes involuntary muscle contractions. Although this often occurs when tense, tight back muscles are present, it can happen in any circumstance.s a result of the contraction people often complain of having symptoms of either a locked back, or a knot in their back. Among the most common causes of muscle spasms in the back... 1  a sneeze or cough. 2  lifting heavy objects. 3  incorrect sitting posture. 4  muscle overuse, or injury. 5  dehydration.