Final answer:
The best follow-up step is HPV typing to determine if the patient has a high-risk HPV type. This step is indicated due to her history of genital warts and an abnormal Pap smear, guiding the need for further surveillance or treatment.
Step-by-step explanation:
The most appropriate next step in the management of this patient, who is a 25-year-old woman with a recent abnormal Pap smear showing atypical squamous cells of undetermined significance (ASCUS) and a history of genital warts, is HPV typing. Genital warts are caused by certain strains of the human papillomavirus (HPV), which is also a known cause of cervical cancer. Considering her smoking history and the finding of ASCUS, it is important to identify whether she has a high-risk HPV type that might warrant closer surveillance or intervention.
The current guidelines recommend that women aged 21 to 65 should receive routine Pap smears every 3 years. In cases of abnormal Pap smear results, such as ASCUS, reflex testing for HPV is often recommended, particularly for women aged 25 or older. If the HPV test is positive for high-risk types, further diagnostic procedures such as colposcopy or a more definitive treatment may be indicated. Therefore, HPV typing is the most suitable follow-up step for this patient.
Contrary to options like repeat Pap smear in three years, cone biopsy, cryotherapy, and Loop Electrosurgical Excision Procedure (LEEP), HPV typing provides necessary information to guide subsequent management without immediately resorting to more invasive procedures which may not yet be needed pending the results of her HPV status.