Final answer:
For a primigravida patient with a palpable thyroid nodule, a thyroid ultrasound is the next appropriate action. This test allows assessment of the nodule's characteristics and helps guide further testing or specialist referral.
Step-by-step explanation:
A 30-year-old primagravida patient with complaints of a hot spot on her neck and a palpable thyroid nodule warrants further examination. The suggested first line diagnostic procedure in this case would be a thyroid ultrasound to determine the nodule's characteristics such as size, structure, and whether it is solid or fluid-filled. The thyroid ultrasound can help determine if additional tests or interventions, such as a biopsy or radioactive iodine uptake, are needed. It also helps the healthcare practitioner decide whether referral to an endocrinologist is necessary at this stage. If the ultrasound suggests a suspicious nodule, then further fine-needle aspiration biopsy may be warranted to check for malignancy. A 24-hour radioactive iodine uptake might be considered based on the ultrasound and biopsy results or if the practitioner suspects a thyroid function anomaly.