Blood tests and staying safe

Before you start taking hormones, you should get a pretty complete baseline set of blood tests:
 * Comprehensive Metabolic Panel (CMP) measuring liver function (so you can rule out liver damage caused by HRT.)
 * Testosterone (Free)
 * Testosterone (Total)
 * Sex-Hormone Binding Globulin (SHBG).
 * DHT
 * Estradiol
 * FSH (indicates activity of the HPG axis)
 * LH (indicates activity of the HPG axis, along with FSH.)
 * Complete Blood Count (CBC) measuring blood and immune system health (rules out illness causing chart weirdness or autoimmune reactions.)

Once you have this baseline, you know what's "normal" for your body. Don't assume you're starting with "normal" ranges; trans people are more likely to be intersex than cis people and many don't know it.

Every month (if you can afford it) or as soon as you've been at a normalish range for a couple weeks, get the following blood tests done:
 * Estradiol
 * Testosterone (Free)
 * Testosterone (Total)
 * DHT
 * FSH
 * LH
 * Comprehensive Metabolic Panel
 * Prolactin (if MTX) (guards against prolactinoma, an occasional side effect of HRT that may cause brain damage.)

If your goal is binary transition, success looks like keeping these numbers in normal ranges for the sex you're transitioning to. If you're taking sex hormone blockers alone (at any age, even past puberty), you'll want to keep estradiol, DHT and T down to pre-pubertal levels. If you're not using bioidentical estradiol or testosterone directly, but some synthetic sex hormone (e.g. Tamoxifen, Trenbolone, be aware that the levels of estradiol and testosterone and DHT you get from these tests will mean little to nothing.

Once your bloodwork looks good and your regimen is staying the same two months in a row, you can get bloodwork done every ~6 months and fewer orders:
 * Estradiol
 * Testosterone (Free) (if MTX)
 * Testosterone (Total) (everybody)
 * DHT (if MTX)
 * Comprehensive Metabolic Panel

Make sure you get bloodwork done the day before you inject (if you inject your hormones) or right before you'd take the pill (if you swallow your hormones.) If you're on testosterone, consider fasting. If you get bloodwork done immediately after you take your hormones, it'll show you a spike that isn't real.

Running your own blood tests
You can order bloodwork orders online. After you've ordered the blood tests, they'll send you a lab requisition order for you to print. Assuming the order is probably for LabCorp, find the nearest LabCorp to you and walk in. A technician will take the order and then your blood, out of those vein things you have. A few days later, your results should appear online! Unfortunately, you have to pay out of pocket and insurance won't cover you.

Private MD Labs
http://www.privatemdlabs.com/ (USA) is excellent.
 * For MTX HRT, order the Hormone Panel with Prolactin.
 * For FTX HRT, order the "Hormone Panel for Females" (note: the test is badly named and the site itself says that "both men and women order this panel."

Reference Ranges
See this list of reference ranges for a full table.

MTX Symptoms to Watch Out For

 * Discharge around the areolas is often fine, but too much may indicate prolactinoma, a serious condition. Get a blood test for prolactin immediately and ease off of hormones until you get results back.
 * Visual disturbances or blindness are more dire signs of prolactinoma.
 * Don't worry too much about prolactinoma as long as you're following the steps and getting regular blood tests. It's far more likely in people who are far out of range on hormones, or people taking synthetic preparations (such as OCP for MTXes, or synthetic steroids for FTXes.)

FTX Symptoms to Watch Out For

 * Please help expand this list!