Frequently Asked Questions

The thousands of blood tests that are performed every day in today’s modern labs fall into four main categories:

  • Hematology
  • Microbiology
  • Biochemistry
  • Serology

Hematology tests examine the blood to identify the following three things:

  • The types and numbers of blood cells that are present — specifically, red blood cells, white blood cells, and platelets
  • The appearance of the cells, especially their maturity
  • The ability and speed for the blood to clot

Biochemistry tests measure the amount of normally occurring chemicals and biochemicals in the blood, both individually and in relation to other chemicals. These measurements are compared to normal ranges for that test and are used to determine whether blood biochemicals are in a proper and healthy balance. Biochemicals and other substances that may be studied include the following:

  • Sodium
  • Hormones
  • Recreational drugs
  • Cholesterol and other fats
  • Blood gases
  • Alcohol
  • Vitamins and minerals
  • Prescription drugs

Biochemical tests can precisely measure these substances and be used to indicate how well some organs and organ systems are functioning. For instance, the amount of blood sugar (glucose) in the bloodstream can help to diagnose or monitor diabetes and indirectly reflect how much insulin is being produced by the pancreas.

Microbiology tests examine blood for the presence of infectious microscopic organisms such as the following:

  • Smears, in which a small amount of blood is placed on a glass slide for examination under a microscope. Sometimes the blood smear is stained with special dyes before examination.
  • Blood cultures, in which a small amount of blood is placed in a nutrient broth, incubated for days or weeks, and then examined for growth of disease-causing bacteria.

Serology tests (those done on blood serum) can detect the presence of antibodies that are produced by white blood cells to attack microscopic organisms. They are frequently used to detect viral diseases. Most hospital laboratories do not have the equipment or specially trained personnel necessary to isolate the viruses themselves, so serology tests are done instead to identify the infecting organism by studying the antibodies produced against it.

We include a heparin anticoagulant coating option in blood collection tubes to reduce the risk of a clot forming in after being collection and before the actual test is performed.

Smoke rings, sometimes called boron haze, may occur when gases are trapped inside the tube during finishing. Sometimes, the smoky appearance is caused by condensation since borosilicate glass is thermally shocked with water.