Pyruvate Kinase Screen (Blood)

Testing Laboratory

Auckland Te Toka Tumai | Auckland Hospital

Department

Haematology

Delphic Registration Code (Alpha Code)

PKSC

Test Code (Numeric Code)

1418

Laboratory Handling

Phlebotomy

Collect:

1x 2m EDTA (Lavendar cap) blood sample.

Paediatrics: 1x 0.25ml micro-EDTA blood sample.

Transport

EDTA - DO NOT SPIN.

CPD samples can be used but not preferred - DO NOT SPIN.

Samples are labelled with suffix.

Load on the 8100.

If a printout of FBC results is received send with sample.

Registration

registered as PKSC

Laboratory

LabPlus Special Haematology

Test Adds Requirement

Only available as test add by Special Haematology.

Sample Stability

PK Enzyme is stable for 6 days at 4 degrees Celsius and 24 hours at room temperature. Any specimens transported overnight should be transported on wet ice.

Synonyms

PK Screen

Turnaround Time

1 day

Analysed daily from Monday to Friday.

Specimen Type

• Whole Blood

Specimen Requirements

Tube/Container Type:

Preferred

• EDTA (Lavender Cap)

Acceptable

• CPD (Yellow Top Tube)

Preferred Sample Volume (ml)

4

Minimum Sample Volume (ml)

2

No of Samples Required

1

Paediatric Specimen Requirements

Tube/Container Type:

Preferred

• EDTA (Lavender Cap)

Acceptable

• EDTA (Microtainer)
• CPD (Yellow Top Tube)

Preferred Sample Volume (ml)

1

Minimum Sample Volume (ml)

0.25

Additional Specimen Information

PK Enzyme is stable for 6 days at 4 degrees Celsius and 24 hours at room temperature.
Patient samples being sent from outside the Auckland area should be accompanied by a control sample.
Any specimens transported overnight should be transported on wet ice.
If the patient has had a blood transfusion in the last 3 months an enzyme screen cannot be performed on this patient. The screening is recommended 3 months after the most recent transfusion.

Aliquot Instructions

Sample Type

• Whole Blood

Minimum Volume (ml)

2

Transport to Lab

Ambient (8 - 24 degrees Celsius)
If overnight - Chilled (2 - 8 degrees Celsius)

Additional Referral/Aliquot Information

Patient samples being sent from outside the Auckland area should be accompanied by a control sample.
Any specimens transported overnight should be transported on wet ice.

Test Method

Manual Process. The loss of fluorescence of NADH in the reaction mixture under long-wave ultra violet light is the basis of this test.

Limitations / Interference

Recent Blood Transfusions: Transfused normal red blood cells mask the deficiency by introducing normal PK activity, leading to false-normal results. Testing should ideally be delayed for 50 to 90 days post-transfusion.
White blood cells and platelets contain high levels of pyruvate kinase. Failing to properly purify red blood cells (such as removing the buffy coat) falsely elevates measured PK activity.

Uncertainty of Measurement

False-normal or false-negative results

The fluorescent spot test is a rapid and reliable procedure for the detection of a deficiency of the enzyme pyruvate kinase.
This enzyme is an important part of the glycolytic metabolic pathway and an absence of this enzyme usually leads to a chronic non-spherocytic haemolytic anaemia.
The severity varies from severe neonatal anaemia and jaundice to well compensated cases detected as an incidental finding.
PK, like G6PD, is a red cell age-dependent enzyme. But unlike G6PD, PK deficiency is usually associated with a chronic haemolysis. Therefore, patients in whom PK deficiency is suspected almost invariably have a reticulocytosis, and if their PK level is below normal, they can be considered to be PK deficient.

Contact Information