A patient with palpitations and muscle twitching may require which diagnostic test?

In the case of a patient presenting with palpitations and muscle twitching, the serum calcium test is a valuable diagnostic tool because abnormal levels of calcium in the blood can significantly affect neuromuscular function. Hypercalcemia, or elevated calcium levels, can lead to muscle weakness, palpitations, and even arrhythmias, while hypocalcemia can cause neuromuscular excitability, resulting in muscle twitching and other symptoms such as tingling and persistent palpitations.

Assessing serum calcium helps to determine whether electrolyte imbalances are contributing to the patient's symptoms, allowing for appropriate management. If the calcium levels are found to be abnormal, it guides further testing and treatment to address the underlying issue.

The other tests, while potentially useful in certain contexts, are not the most direct or relevant in evaluating these specific symptoms related to calcium levels. For example, thyroid-stimulating hormone (TSH) tests would assess thyroid function, which can also cause palpitations, but the presence of muscle twitching aligns more closely with calcium abnormalities. An electrocardiogram (ECG) is important for monitoring the heart but does not address the underlying causes directly. A complete blood cell count (CBC) evaluates general health and detects conditions