there are many blood test. However, I'm going to give you a very specific answer to your question:
Some STDs — some of which can't be fully prevented by condom use — can't be tested for. So even if you ask your doctor to test you for everything, this doesn't mean that you or your partner will be screened for or clear of all STDs.
If you're sexually active, what routine tests are most important?
For women:
At a minimum, get a Pap smear.
For men:
Centers for Disease Control and Prevention (CDC) guidelines don't suggest routine STD screening if you don't have any symptoms, unless your sexual practices include having sex with men.
If you are a man who has sex with men, annual screening for HIV, syphilis, chlamydia and gonorrhea is recommended. HIV and syphilis can be life-threatening if untreated, and chlamydia and gonorrhea can put you at greater risk of acquiring HIV and other STDs.
For men and women:
Also see your doctor for STD testing if you have any signs such as genital sores, including fluid-filled blisters, ulcerations or warts, or if you have unusual discharge from your penis or vagina. If you're a woman, abdominal pain or fever along with unusual discharge may indicate pelvic inflammatory disease (PID) — an STD-related condition that can cause infertility.
The CDC also encourages voluntary HIV testing, at least once, as a routine part of medical care if you are an adolescent or adult between the ages of 13 to 64. The CDC advises yearly HIV testing if you are at high risk of infection, for example if you've had unprotected sex with more than one sexual partner since your last screening.
Gonorrhea and chlamydia
If you are a sexually active girl or woman under age 24, or a woman older than 24 and at risk of STDs — for example you are having sex with a new partner or multiple partners — get screened annually for gonorrhea and chlamydia. If untreated, these infections can cause PID in women. Gonorrhea and chlamydia can also significantly increase your risk of acquiring other STDs like HIV. If you are a man who has sex with men, get tested for these infections at least annually
Gonorrhea and chlamydia screening is either done through a urine test or through a swab inside the penis in men or from the inside of the cervix in women
Syphilis, hepatitis and HIV
If you test positive for gonorrhea or chlamydia, you're at greater risk of other STDs such as syphilis, HIV and hepatitis and should get tested for these infections
Your doctor tests you for syphilis by taking either a blood sample or a swab from any genital sores you might have. The sample is examined in a laboratory. A blood sample is taken to test for HIV and hepatitis A and B.
It's possible that you may test negative for syphilis or HIV if you've only just recently acquired the infection. If you or your doctor suspects this is the case, you may need to be rescreened at a later date. Talk with your doctor if you have concerns about this.
Consider vaccination for hepatitis A and B. You can prevent these infections by receiving the vaccines.
Genital herpes
Unfortunately, no good screening test exists for herpes, a viral infection that can be transmitted even when a person doesn't have symptoms. Your doctor may take a tissue scraping or culture of blisters or early ulcers, if you have them, for examination in a laboratory. But a negative test doesn't rule out herpes as a cause for genital ulcerations.
. Some blood tests don't distinguish between types 1 and 2 of the herpes virus. Type 1 is the virus that more typically causes cold sores, although it can also cause genital sores. Type 2 is the virus that more typically causes genital sores. You may ask for a "type-specific" IgG blood test, which differentiates between the two, measuring antibodies to the viruses in your blood. Still, the results may not be totally clear, depending on the sensitivity of the test and the stage of the infection. False-positive and false-negative results are possible
HPV
HPV, an infection that can be transmitted even when a person doesn't have symptoms, is a condition contracted from one of a group of more than 100 related human papillomaviruses (HPVs
The HPV DNA test can test for both low-risk types of HPV, which may cause genital warts, and high-risk types that may cause cervical cancer
Girls and women ages 9 to 26 can help prevent HPV infection by receiving the HPV vaccine. This vaccine protects against the two strains that cause 70 percent of cervical cancers and the two strains that cause 90 percent of genital warts.
Are all STD tests always done?
No, as mentioned earlier, men should receive testing if they have symptoms, have sex with other men, or if a partner tests positive for an STD. In women, HIV, syphilis and hepatitis testing may be done if other STDs are present. Testing for herpes is only usually done if symptoms are present. And HPV testing isn't available for men, and only sometimes done for women older than 30.
On diabetes; two tests are gold standard: Fasting Blood sugar levels and oral Glucose Tolerance Test.
The hemoglobin (hgb) A1c blood test is like a 2-3 month average blood sugar. What you ate the night before the Hgb A1c blood test does NOT affect the result. The test can be done at any time of the day in a lab using a sample of blood from your arm.
http://diabetes.webmd.com/guide/diagnosing-type-2-diabetes
http://www.diabetes-blood-sugar-solutions.com/a1c-blood-test.html
For Drug testing: Toxicology screen refers to various tests to determine the type and approximate amount of legal and illegal drugs a person has taken. Unless specifically ordered by the doctor, these drugs won't be identified unless tested for.
http://www.nlm.nih.gov/medlineplus/ency/article/003578.htm