The short answer is no. The diagnostic guidelines require at least two readings over 140/90 (either number) at least four hours apart after 20 weeks, plus at least one other diagnostic symptom. You do need high blood pressure for a diagnosis of preeclampsia.
Source: ACOG's Hypertension in Pregnancy (2013), page 13
The longer answer has some caveats:
Your blood pressure does not need to be continuously high. The diagnostic criteria only require two high readings. It is not unusual for blood pressure to fluctuate up and down before it stays high. So it may not be high at this very minute, but you could still have preeclampsia if you have had some high readings, along with other diagnostic symptoms. At the very least, fluctuating blood pressure should earn you closer monitoring.
If you have a very low baseline pressure (like 90/60), an increase of 30/15 points is worth keeping a close eye on. By itself it could be nothing, just part of the slow creep upward that is common in late pregnancy. But if you have other concerning symptoms, they should not be ignored just because your high-for-you pressure is not technically high. Doctors treat patients, not textbooks, and should take the whole picture of a patient’s history and health into account.
It is possible, though rare, to have HELLP syndrome without preeclampsia and with normal blood pressure. HELLP falls under the umbrella of conditions that is often referred to generally as preeclampsia. A doctor may call HELLP preeclampsia (general), even if it does not meet the specific criteria for preeclampsia because blood pressure is not high.