Preanalytical variability: turning dark into bright. Gian Luca Salvagno, Verona, Italy

Errors and patient’s outcome 1999 a.c.

Radiological mistakes 2001 Laboratory Errors 1997 Miss luggage in airport Laboratory Errors 2007

The clinical perspective...

The economic perspective... Sample recollection

The organizational perspective...

1° 4° 2° 3° 5°

Patient preparation Sample collection Sample transport Sample storage Biological variability Posture Patient identification Sample collection Collection system Needle Venous stasis Order of draw Phlebotomy procedure Contamination Tube mixing Sample transport Transport condition Pneumatic tube systems Sample storage

Fasting requirements

Fasting requirements

Fasting requirements

Fasting requirements

Fasting requirements

Patient preparation Sample collection Sample transport Sample storage Biological variability Posture Patient identification Sample collection Collection system Needle Venous stasis Order of draw Phlebotomy procedure Contamination Tube mixing Sample transport Transport condition Pneumatic tube systems Sample storage

Posture Inpatient Outpatient Just arrived in the ED

Posture

Posture X DAY 1 DAY 2

Posture

Posture

Posture

Patient preparation Sample collection Sample transport Sample storage Biological variability Posture Patient identification Sample collection Collection system Needle Venous stasis Order of draw Phlebotomy procedure Contamination Tube mixing Sample transport Transport condition Pneumatic tube systems Sample storage

Misidentification: Relatively rare (2%), but the worst!

Healthcare institutions should have zero tolerance to patient identification errors; A minimum two and preferably three unique patient identifiers (one of which is the full name of the patient) should be used for patient identification; Patient and sample identity should always be checked in the presence of the patient; The institution should have a policy and a written standard operating procedure defining the patient and sample identification, which is followed by all personnel; The institution should have a system in place to continuous monitor and hopefully reduce the frequency of the identification error rate; A system should be in place for a continuous education for all professions involved in phlebotomy; EFLM member societies should adopt these recommendations and encourage their implementation among healthcare institutions at their national level; Standard writing bodies (CLSI, ISO) are encouraged to consider the present recomendations

Patient preparation Sample collection Sample transport Sample storage Biological variability Posture Patient identification Sample collection Collection system Needle Venous stasis Order of draw Phlebotomy procedure Contamination Tube mixing Sample transport Transport condition Pneumatic tube systems Sample storage

Blood drawing: The leading source of “our” problems!

Blood drawing -0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 Median cephalic Median basilic Median anterobrachial Cephalic Basilic Metacarpal plexus Cell-free hemoglobin (g/L) Blood collection from veins of the metacarpal plexus discouraged: Hemolysis decreased by approx 30%

Tube validation

Tube validation

Tube validation

Patient preparation Sample collection Sample transport Sample storage Biological variability Posture Patient identification Sample collection Collection system Needle Venous stasis Order of draw Phlebotomy procedure Contamination Tube mixing Sample transport Transport condition Pneumatic tube systems Sample storage

CONCLUSIONS: We suggest that, when a proper technique is used and within certain limitations, the butterfly device may be a reliable alternative to the conventional straight needles to draw blood for lab testing.

Patient preparation Sample collection Sample transport Sample storage Biological variability Posture Patient identification Sample collection Collection system Needle Venous stasis Order of draw Phlebotomy procedure Contamination Tube mixing Sample transport Transport condition Pneumatic tube systems Sample storage

USE OF TOURNIQUET: (a) The tourniquet should be applied to the area approximately 10 cm above the intended site of venipuncture. (b) It should be tight enough to restrict venous flow but not tight enough to obstruct arterial circulation. The pulse should be palpable below the level of the tourniquet. (c) The tourniquet should not be left in situ for >1 min (when more time is required to find a suitable vein or the venipuncture protracts, the tourniquet may be released and reapplied). (d) When vein is selected, tourniquet is released, skin cleansed and allowed to dry, then tourniquet re-tightened to proceed with venipuncture. (e) Once blood flow starts (or needle is safely in vein), tourniquet is released. Should flow diminish or cease before sufficient blood is obtained, the tourniquet may be reapplied lightly. (f) Tourniquet should not cause pain or discomfort to patient.

Patient preparation Sample collection Sample transport Sample storage Biological variability Posture Patient identification Sample collection Collection system Needle Venous stasis Order of draw Phlebotomy procedure Contamination Tube mixing Sample transport Transport condition Pneumatic tube systems Sample storage

Patient preparation Sample collection Sample transport Sample storage Biological variability Posture Patient identification Sample collection Collection system Needle Venous stasis Order of draw Wipe alcohol? Fist clenching? Underfilling? Phlebotomy procedure Contamination Tube mixing Sample transport Transport condition Pneumatic tube systems Sample storage

(Avoiding fist clenching)

Underfilling

Patient preparation Sample collection Sample transport Sample storage Biological variability Posture Patient identification Sample collection Collection system Needle Venous stasis Order of draw Phlebotomy procedure Contamination Tube mixing Sample transport Transport condition Pneumatic tube systems Sample storage

Is cross-contamination of blood tubes a significant cause of bias?

Patient preparation Sample collection Sample transport Sample storage Biological variability Posture Patient identification Sample collection Collection system Needle Venous stasis Order of draw Phlebotomy procedure Contamination Tube mixing Sample transport Transport condition Pneumatic tube systems Sample storage

Patient preparation Sample collection Sample transport Sample storage Biological variability Posture Patient identification Sample collection Collection system Needle Venous stasis Order of draw Phlebotomy procedure Contamination Tube mixing Sample transport Transport condition Pneumatic tube systems Sample storage

Spoke Spoke Spoke HUB Spoke Spoke Spoke Spoke Spoke

The 13 commandments: Separate serum or plasma from blood cells ASA but not later than 4 h Use tube separators or aliquot serum and plasma ASAP Keep tubes and aliquots safely capped Keep tubes in vertical position during transport Use validated biohazard containers for transport Use first/second/third level containers Ensure stable conditions of temperature (i.e., 18-25°C) and humidity Avoid light exposure Prevent trauma of specimens Deliver to the corelab as ASAP Record transportation time (from start to arrival to the lab) Monitor conditions throughout transportation Reject samples with unsuitable conditions of transport

Data relating to sample stability may strongly depend on the tube type used for blood collection, (including any separation gels, anticoagulants and other additives present), the temperature of storage prior to testing, and the laboratory method used for determination. The mode of transporting samples to the laboratory may be relevant, as well.

Patient preparation Sample collection Sample transport Sample storage Biological variability Posture Patient identification Sample collection Collection system Needle Venous stasis Order of draw Phlebotomy procedure Contamination Tube mixing Sample transport Transport condition Pneumatic tube systems Sample storage

The conclusions of some papers show no preanalytical errors in samples transported for analysis of routine hematology, coagulation parameters and platelet function with the PFA-100. But, putting together the data, current evidence on the effects of PTS on the quality of patient samples is not satisfactory.

Pre-analytical Processes Quality Indicators… A long and winding road ahead.

THE LABORATORY IN DIAGNOSIS

Sten Westgard, January 2006. http://www.westgard.com/lesson83.htm