The following is a brief overview of the requirements involved for collecting
blood specimens. Each of the different tubes has individual characteristics.
In general, all the tubes are to be mixed well by gently inverting several
times after filling with blood. Tubes are full when the vacuum quits drawing
blood into the tube.
Serum type tubes
Red-Top Tube
This tube is a plain Vacutainerâ containing no anticoagulant, used for
collection of serum specimens. Tests using this tube may include therapeutic
drugs, selected chemistry tests and some blood bank procedures. Any chemistry
sample may be collected in these tubes. However, the yellow-top SST tubes
are superior as the serum is automatically separated. When a test is designated
to be collected in a red-top tube, an SST tube should not be substituted.
The gel barrier may interfere with analysis.
Yellow-Top Serum Separator Tube (SST)
This tube contains a clot activator and a serum gel separator, used for
various laboratory tests, including the majority of chemistry tests. Invert
the tube six to ten times in order to activate the anticoagulant.
Plasma and whole blood tubes
Blue-Top Tube (Sodium Citrate)
This tube contains sodium citrate as an anticoagulant, used for collection
of blood for coagulation studies. NOTE: It is imperative that the tube
be completely filled. The ratio of blood to anticoagulant is critical
for valid coagulation studies. Immediately after draw, invert the tube
six to ten times in order to activate the anticoagulant.
Gray-Top Tube (Potassium Oxalate/Sodium Fluoride)
This tube contains potassium oxalate as an anticoagulant and sodium fluoride
as a preservative, used to preserve glucose in whole blood and for some
special chemistry tests. The minimum volume should not be less than 1.0
mL due to the anticoagulant present in the tube.
Green-Top Tube (Lithium Heparin)
This tube contains lithium heparin, used for the collection of heparinized
plasma or whole blood. The minimum volume should not be less that 1.0
mL due to the anticoagulant present in the tube.
Green-Top Tube (Sodium Heparin)
This tube contains sodium heparin, used for the collection of heparinized
plasma or whole blood for special tests. The minimum volume should not
be less than 1.0 mL due to the anti-coagulant present in the tube.
Lavender-Top Tube (EDTA)
This tube contains EDTA as an anticoagulant, used for most hematological
procedures. Mix the tube well to dissolve the powdered anticoagulant.
The blood level should at least reach the bottom of the tube’s label.
NOTE: Never shake the tubes to mix. Shaking will fragment the blood cells
and could result in false abnormal hematology findings.
Light Yellow-Top Tube (ACD)
This tube contains ACD, used for the collection of whole blood for special tests.
NOTE: This tube is very similar in appearance to the SPS tube. Read the
label for verification of correct anticoagulant.
Light Yellow-Top Tube (SPS)
This tube used for the collection of blood cultures contains, SPS, is
always drawn first to avoid bacterial contamination.
NOTE: This tube is very similar in appearance to the ACD tube. Read the
label for verification of correct anticoagulant.
Pink-Top Tube (EDTA)
This tube contains EDTA as an anticoagulant, used for most blood bank
procedures. Mix the tube well to dissolve the powdered anticoagulant.
Royal Blue-Top Tube
There are two types of royal blue-top Monojectâ tubes, one with the anticoagulant
EDTA and the other plain. These are used in the collection of whole blood
or serum for trace element analysis. Refer to the individual metals in
the specific test listing to determine the tube type necessary.
Tan-Top Tube (Sodium Heparin)
This tube is lead-free and thus used for collection of blood lead levels.
White-Top Tube (K2 EDTA)
This plasma preparation tube (PPT) contains a gel barrier in the plastic
tube. After centrifugation the plasma may be frozen without opening the tube.
Miscellaneous tubes
Microtainers
These are designed for fingersticks, which are commonly used for children
or other difficult venipunctures. (Some vials may contain a powdered form
of the anticoagulant. This must not be shaken out as the vial is being mixed.)
- Peach/red - no anticoagulant
- Yellow top; Amber tube - no anticoagulant, protects specimen from light.
- Green - heparinized anticoagulant
- Lavender - EDTA anticoagulant
NOTE: All hematology collections (CBC, hemoglobin, hematocrit, etc.) must
be well mixed. Any clotting will cause the results to be invalid. When
collecting the specimen and the blood flow is slow, cap the vial and mix
quickly midway through the blood collection. This will help prevent a
clot formation. Mix again at the completion of the collection. The minimum
collection is at the second purple line (500 ml).
Pediatric Tube (Half-draw)
The half-draw tubes, which have clear lids, are designed for children
or patients who are difficult to draw. These tubes contain a smaller amount
of vacuum, thus less trauma to the vein. Because of the reduced amount
of anticoagulant, as well as vacuum, it is important not to overfill these
tubes. This is possible if filled by a syringe. Overfilling could cause
rejection of the specimen. On some tubes, the proper fill line is marked
with small blocks halfway up the edge of the label.
Special Collection Tubes
Some tests require specific tubes for proper analysis, (such as metals).
Please contact Meadville Medical Center Laboratory prior to patient draw
to obtain the correct tubes as identified in the individual test listings.