How Is Hypertension Diagnosed?
A blood pressure measurement is as simple as applying a blood pressure cuff, inflating it, and listening over the artery with a stethoscope. When the pressure in the cuff is enough to stop arterial pulsations or have them resume (systolic blood pressure), and when the pressure from the cuff against the artery is low enough to prevent the turbulence of arterial blood flow from vascular resistance (diastolic blood pressure), each of these pressures give the two numbers use in blood pressure.
There is no official line that one can cross to have hypertension, that is, clinically relevant to impact health. But the blood pressure relationship with cardiovascular disease is a gradual one which has no isolated red flags at any one point. Therefore, it is important to observe for hypertension via several readings over time and vigilance for any complications of hypertension.
Diagnosis of Hypertension
Criteria are different for different providers, but in general:
- Serial office setting blood pressures: at least 3 readings spaced out over weeks to months.
- Since a BP reading in the office setting can be spuriously high due to nervousness or a hurried day to fit the appointment into one’s day, out-of-office settings like with home monitoring are beneficial toward diagnosis.
- Home monitoring affords an excellent appraisal by adding as many readings as the patient can do. More information is always better than less information.
- Ambulatory blood pressure monitoring (ABPM) can be indicated in cases in which home monitoring is not possible or is inaccurate.
This involves on-going readings using a cuff and a digital device for recording. If the mean daytime BP is ≥130/≥80, the diagnosis is made.
Serial blood pressure readings are not needed when a patient presents with a BP ≥180 systolic/≥120 diastolic or who has end-organ damage with an initial reading of ≥160 systolic/≥100 diastolic.
- Blood tests: electrolytes, calcium, and serum creatinine; fasting glucose; complete blood count; thyroid stimulating hormone (TSH), lipid profile
When hypertension is found to be secondary to causes identified in blood work, ECG, or from renal disease, other testing may be necessary:
- Renal function: urinary albumin to creatine ratio, since increased albumin in the urine is a risk factor for cardiovascular disease. Also, many electrolyte imbalances call for renal and endocrine testing.
- Hemoglobin a1C for diabetics
- T3 and T4 thyroid levels when the TSH is elevated
- Cardiac echogram if hypertension is suspected of having untoward effects on the heart and to evaluate for atherosclerosis
- Peripheral vascular echograms to identify arteriosclerosis and venous insufficiency