Tubes and Testing Flashcards
(31 cards)
Purple Top
EDTA; Creates a whole blood sample; CBC and blood smears; invert tube 8-10x immediately
Red Top
No additive; Serum chem, therapeutic drug monitoring, some serology; allow clotting for 15-30 mins, then centrifuge
Tiger Top
Clot activator and gel separator; serum chem, similar to red top but more convenient; 15-30 to clot, then centrifuge
Green Top
Heparin; plasma chemistry, blood gas analysis, sometimes PCV/TS
Blue Top
Sodium citrate; coat profiles (PT/aPTT); invert 3-4 times must be filled to indicator line
Grey Top
Sodium Flouride/Potassium Oxalate; Blood glucose monitoring, lactate; invert 8-10 times
Define: Packed Cell Volume (PCV) or Hematocrit (HCT)
Measures the percentage of RBC’s in a whole blood sample (EDTA or Heparinized); Indicates the oxygen carrying capacity of the blood; indicator anemia or dehydration
Define: Total Solids (TS) or Total Protein (TP)
Measures the amount of protein in the plasma portion of the blood using a refractometer. Helps assess hydration status, inflammation, liver, and kidney function
Supplies for a PCV/TS
- Whole blood (EDTA or Hep)
- microhematocrit tubes x2 (to balance centrifuge)
- clay sealant
- microhematocrit centrifuge
- microhematocrit card or ruler
- Refractometer
SOP: PCV/TS preparation
Sample Prep: collect blood sample in a lav top or green top
Fill tubes: Hold hematocrit tube horizontally and touch one end to the blood sample, allow it to fill until about 2/3 full
Seal Tubes: Press clear (empty) and into clay sealant
Centrifugation: Place tubes seal ends outwards towards rubber gasket and directly opposite of each other. Spin according to manf.
SOP: PCV interpretation
Sample will have 3 layers:
1: Packed RBC’s; on the bottom, darker
2: Buffy Coat; thin, whiteish layer above RBC’s composed of WBC’s and platelets. Take note of thickness. Thicker can=inflammation/infection
3: Plasma ; clear to yellowish liquid on the top. Take note of color. clear=WNL, yellowish=icteric, red=hemolyzed, cloudy=lipemic
Align bottom of the red cell column with the 0 line and the top of the plasma with the 100 line. Read the value at the top of the red cell column, record at a %
SOP: TS interpretation
- Carefully break the microhematocrit tube just above the Buffy coat, near the plasma layer
- place a drop of the plasma onto the refractometer
- read value on the “Total protein” scale
Define: Blood Smear
A thin layer of blood spread on a glass slide, stained, and examined under a microscope. It allows for detailed evaluation of red blood cell morphology (shape, size, color), white blood cell differential count (identifying different types of WBCs and their proportions), and platelet estimation. It can also reveal blood parasites or abnormal cells.
Supplies for a blood smear
- Fresh whole blood (EDTA)
- 2-3 glass slides per sample
- spreader slide
- microscope
- diff-quick or romanowsky
-immersion oil
SOP: Blood smear preparation
- label the frosted end of the slide with patients name and date
- place a very small drop of blood (1-2mm) apprx. 1-2cm from frosted end of slide
- hold labeled slide flat on stable surface
- place spreader slide @ 30-45 degree angle just in front of blood drop
- gently pull spreader slide back onto blood droppings and allow blood to spread by capillary action along the edge of the slide
- push forward in a smooth, rapid motion keeping constant pressure until reach the end of labeled slide
- allow to completely air dry
- stain!
- rinse w. distilled water and allow to air dry again
SOP: Blood smear interpretation
- low power (10x): Scan the entire smear to assess overall quality, cell distribution, and to locate the “monolayer” (area where cells are evenly spaced and not overlapping). Check for platelet clumps and large parasites.
- high dry power (40x): Evaluate the general morphology of RBCs, WBCs, and platelets. Perform a WBC differential count (identifying and counting 100 WBCs, noting their proportions). Estimate platelet count.
- Oil immersion (100x): Examine RBC morphology (size, shape, color, presence of inclusions like Heinz bodies or blood parasites). Perform a detailed review of WBC morphology, confirming differential counts, and looking for subtle abnormalities or intracellular organisms. Confirm platelet estimation and look for macroplatelets or platelet aggregates.
Describe: Urinalysis
A comprehensive assessment of urine that provides information about kidney function, hydration status, urinary tract infections, and various metabolic diseases. It involves three main parts: physical examination, chemical analysis, and microscopic sediment evaluation.
Urinalysis supplies
- fresh urine sample
- urine dipstick
- refractometer
- conical centrifuge tubes
- microscope slides and coverslips
- Sedi-stain, new methylene blue (optional)
SOP: Urinalysis gross examination
Color: yellow, amber, colorless, red/brown
Clarity/Turbidity: Clear, slightly cloudy, cloudy, turbid
Volume: notable if collected with free catch
Odor: Note if sweet/fruity (DIABETES!!) or extra ammonia
SOP: Urinalysis Specific Gravity
- Place drop of urine on the refractometer
- Read USG (eg 1.025)
crucial indicator of kidney concentrating ability
SOP: Urinalysis Chemical Analysis
- dip reagent strip fully into the urine sample and draw up alone the edge to remove excess and/or blot with paper towel
- read at timed intervals: compare the color changes on each pad to the color chart on the dipstick container at the specified times.
SOP: Urinalysis Sediment Centrifugation
- Pour 2-10mL of urine into a conical centrifuge tube
- make sure centrifuge is balanced
- centrifuge for 3-5 mins at a moderate speed (e.g., 1500-2000 rpm) do NOT used high speed
SOP: Urinalysis Microscopic Sediment Exam Prep (after centrifuge)
- carefully pour off the liquid portion (decant the supernatant for the fancy ppl), leaving only about 0.5mL of urine and the sediment at the bottom
- resuspend sediment by gently tapping tube
- place one drop of the resuspended sediment onto a microscope slide w a coverslip (opt. to add stain atp)
SOP: Urinalysis Microscopic Sediment Exam
- Low power (10X): Scan the entire slide, focusing on the edges, to locate and identify crystals, casts, and overall cellularity. Quantify casts and larger crystals (e.g., few, moderate, many per low power field).
- High power (40x): Switch to high power to identify and quantify cells (RBCs, WBCs, epithelial cells) and smaller crystals. Quantify cells (e.g., 0-5, 5-10, >10 per high power field). Look for bacteria.
