Cystometry is test. Is a urologic test, performed by filling bladder with fluid or air whilst measuring pressures and monitoring sensation. Unusual if not performed by or under supervision of a urologist or a urogynecologist. That dr. Should discuss findings and implications with you.
Abnormal cystometry. I assume by abnormal cystometry you mean a bladder test that measures your bladder capacity, emptying, and whether your bladder is poorly contractile and can't empty, or overactive and have urgency and urge incontinence. If you are a woman and have a normal urinalysis, probably nothing more but if male or have abnormal urinalysis then a cystoscopy should be done.