Lab
                                ===
þ UA
  <UA.TXT>

þ Urine Dipstick false + and false -
  <UA-False.TXT>

þ Order of geting tubes:
  (Email fromMercy pathologist)
  > Today I was investigating a questionable PT result on a patient, and I
  > suspected that the correct order of draw may not have been followed. One
  > day the patient's PT result was > 90, and the next day it was 15.  I
  > asked 2 different personnel in one of your departments what the correct
  > order of draw for a blue top, purple top, and green top tube would be.
  > Neither was aware that there was a required order of draw. Although I
  > can't prove that this was the problem with this patient's result, it
  > most likely was.
  >
  > The important fact to remember is that different tubes have different
  > substances in them that can interfere with results, if the tubes are not
  > drawn in the correct order. For example, purple top tubes contain EDTA
  > and green top tubes contain heparin, both of which will cause inaccurate
  > results for PT and PTT, if they get into the blue top tube.
  >
  > The correct order of draw is on page 11 of the lab manual, which can be
  > found at the Mercynet site:
  >
  >                             Additive
  >     First:  Pink/Red        None
  >             Blue            Sodium citrate
  >             Gold            None, but contains a clot activator
  >             Green           Heparin
  >             Lavender        EDTA
  >             Yellow          Acid citrate dextrose
  >             Dark blue       None (used for metals)
  >     Last:   Gray            Sodium fluoride

þ Gaps:
  <L-Gap.TXT>

þ Tests of Hemostasis
  <L-Hem.TXT>

þ Bicarbonate Measurement on SMA:
  <L-HCO3.TXT>

þ CO levels:
  <L-CO.TXT>

þ Fecal occult blood (guaiac; hemoccult)
  <L-Guaiac.TXT>

þ Drawing Labs from an IV or Saline Lock:
 - If one stopped the IV infusion for 2 minutes before drawing the blood
   specimen the analysis of CBC and electrolytes did not differ from direct
   venipuncture except for an artifactual decrease in the serum HCO3 (and an
   increase in Glucose after the infusion of D5W).  If a 5 cc aliqout of blood
   was discarded even glucose could be reliably assayed from a previously
   functioning IV site.  The decrement in HCO3 was ascribed to the small
   amount of blood obtained relative to the size of the vacutainer tube which
   allowed CO2 to escape. Surely, what's good for recently discontinued IV
   lines is good for heplocks.
   --H. Louzon MD
   [Herr et. al.  Intravenous Catheter Aspiration for Obtaining Basic
   Analytes During Intravenous Infusion.  Ann Emer Med 1990;19:789-792.]