Test result for alk phosphatase below standard range. others (total bilirubin, bun, albumin, total protein) also low. what could this mean? next step?

Stop worrying: Low alk phos means nothing whatsoever. Reference ranges are set so that a few percent of healthies fall outside on either end. Glad you're interested in lab work. For most labs, worrisome results are way outta range.

See your clinician: There may be nothing "wrong" with you. Note that no test is perfectly accurate. Also, if you're at very low risk for a disease, an abnormal result is less likely to be true. You need to sit down with a clinician to review your tests in light of your overall personal & family medical history, physical findings, & health goals. Next steps include further tests, & watch & wait. Hope that helps.