POCT Blood Gas

Purpose:
The Programme aims to assess the performance of organisations utilising blood gas analysers to aid in the diagnosis of the patient’s acid base balance and the status of routinely measured electrolytes and metabolites.

The Programme is available to both Laboratory and Point of Care testing sites and offer the complete repertoire of blood gases including calculated parameters, electrolytes and metabolites with a separate sample and programme available for Co-oximetry analysis.

Scope:
The standard aqueous material includes the addition of protein which minimises the risk of preanalytical sampling error due to the protein foam layer. The protein material also highlights errors in electrolyte analysis that cannot be detected by other aqueous controls. The tonometered protein based aqueous material is distributed monthly, covering blood gases, electrolytes and metabolites including Haematocrit, Urea, Creatinine and Lactate.

A wide clinical range is covered including challenging samples at low pO2 and low iCa++ concentration. The latter is suitable for the evaluation of instruments used in the monitoring of patients on citrate anticoagulation for Continuous Renal Replacement Therapy (CRRT).

Once a year, tonometered whole blood is distributed as an accuracy check in addition to the aqueous material. This material has identical oxygen saturation characteristics to fresh whole blood and is used to provide an assessment of accuracy for pO2 (especially at low pO2) and in the evaluation of derived parameters (SBC, BE and Oxygen Saturation). The haemoglobin buffering in this material provides a 10-minute open ampule stability.

Three aqueous samples are distributed monthly, with a minimum of 33 samples distributed over the year covering a wide clinically relevant range. The samples consist of a panel of 6 linearly related samples distributed on a number of occasions over that period which are used to assess both laboratory and method performance, including linearity, bias, within and between batch imprecision. Participants can also select to receive three samples 6 times a year.

Key Features:

Weqas’ aqueous material minimises the risk of pre-analytical error sampling due to its protein foam layer.
Additional stable whole blood material distributed once a year for accuracy assessment of pO₂ and additional secondary parameters; base excess and Oxygen Saturation.
Wide clinical range covered over the course of the year including challenging samples.
Programme assesses both laboratory and method performance, including bias, within and between batch imprecision.
Both materials are suitable for use for the majority of PoCT and Laboratory analysers.

Frequency:
Bimonthly

Samples:
3 x 2.5mL

Material:
Tonometered protein buffered aqueous solution and whole blood

Blood Gas Programme
Analyte	Approx. Range Covered
pH	7.0 - 7.7
H+	20 - 100	nmol/L
pCO2	2 - 10	kPa
pO2	4 - 25	kPa
Actual Bicarb	20 - 30	mmol/L
TCO2	15 - 35	mmol/L
Na+	115 - 160	mmol/L
K+	2 - 6	mmol/L
Cl	76 - 123	mmol/L
Magnesium	0.4 - 1.6	mmol/L
iCa++	0.2 - 1.8	mmol/L
Glucose	1.9 - 23.0	mmol/L
Lactate	0.3 - 6.5	mmol/L
Urea	2.8 - 25.0	mmol/L
Creatinine	30 - 560	µmol/L
Haematocrit (iStat only)	0 - 70	%PCV
Lithium	0.35 - 1.35	mmol/L
SBC	20 - 30	mmol/L
BE	-5 to +5
sO2	90 - 100	%