CBC, Chem7, coags
Blood cultures
Shunt tap if concerned for infection (this is usually done by or in consultation with neurosurgery)
A normal lumbar puncture does not rule out ventriculitis (shunt infection)
Imaging
Shunt series
AP and lateral skull, AP chest and abdomen
Identifies kinking, migration, or disconnection
CT
Needed to evaluate ventricular size (if larger, concerning for elevated ICP)
Very helpful to compare to previous study (many patients with shunts have abnormal baseline)
One-third of patients with shunt malfunction will have normal head CT[citation needed]
Ultrasound
If the baby has an open fontanelle, you may use US
Some literature for ultrasound of optic nerve diameter (if normal (3.3cm), lower chance of elevated ICP)[citation needed]
A normal lumbar puncture does not rule out ventriculitis (shunt infection)
Shunt series
AP and lateral skull, AP chest and abdomen
Identifies kinking, migration, or disconnection
CT
Needed to evaluate ventricular size (if larger, concerning for elevated ICP)
Very helpful to compare to previous study (many patients with shunts have abnormal baseline)
One-third of patients with shunt malfunction will have normal head CT[citation needed]
Ultrasound
If the baby has an open fontanelle, you may use US
Some literature for ultrasound of optic nerve diameter (if normal (3.3cm), lower chance of elevated ICP)[citation needed]
AP and lateral skull, AP chest and abdomen
Identifies kinking, migration, or disconnection
Needed to evaluate ventricular size (if larger, concerning for elevated ICP)
Very helpful to compare to previous study (many patients with shunts have abnormal baseline)
One-third of patients with shunt malfunction will have normal head CT[citation needed]
If the baby has an open fontanelle, you may use US
Some literature for ultrasound of optic nerve diameter (if normal (3.3cm), lower chance of elevated ICP)[citation needed]
Ventriculoperitoneal shunt complications
Ventriculoperitoneal shunt obstruction
Ventriculoperitoneal shunt mechanical failure
Ventriculoperitoneal shunt overdrainage 
Ventriculoperitoneal shunt infection
Ventriculoperitoneal shunt overdrainage
Separate, noncommunicating CSF accumulations may develop within a ventricle
Brain herniation syndromes