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Special instructions


Tests displayed on this website may display numbers in square brackets after the sample type required. These numbers relate to special instructions, see below a guide for each instruction.

Code Instruction
1 Contact the laboratory for special sample tubes/containers/instructions.
2 Confirmation of not negative drug screens by LC-MS/MS may take up to 5 days.
3 Clinical history essential and protect from light.
4 Send to the laboratory same day.
5 Do not send sample to the laboratory between Friday noon and Monday morning.
6 Contact the Referrals Department before taking and sending sample to the laboratory.
7 Sample should be separated and frozen if sending overnight.
8 DRP Form required. DRP Form can be found at the back of the guide.
9 Clinical history must be provided.
10 Contact the laboratory for special stability tubes for lymphocyte subsets – or take an EDTA sample and ensure same day delivery to the laboratory, Monday to Friday noon (do not send sample between Friday noon and Monday morning).
11 Patient consent required. See Request forms
12 Please provide one sample for each person being tested.
13 Protect from light.
14 Provide details of travel history.
15 Ammonia
Sample: EDTA plasma only. Full tubes and tightly stoppered. On ice, centrifuged and analysed 20-30 mins post venepuncture (or plasma can be frozen). If haemolysed gives falsely high results. Patient: Fasting. Avoid smoking.
16 Lactate
Sample: Fluoride oxalate plasma only. On ice and separate from cells 15-30 mins, analyse promptly. Handle with care as sweat contains large amounts of lactate. No tourniquet. Patient: Rest 30 mins prior to test.
17 Homocysteine
Should be spun and separated within 1 hour of venepuncture.
18 Citrate Samples
Samples should be double spun and separated and frozen within 4-8 hours of sample taking, if a delay is expected with transportation to the laboratory, samples must be transported as frozen.
19 Must include patient’s age, height and weight.
20 Sample types: FCRU or PCR swab or TPV or Semen.
21 Urine cytology container, ideally first catch, mid-morning specimen.
22 Must be fresh.
23 For Fabry’s Syndrome
24 Anti-malarial drug.
25 Includes: potassium, magnesium, calcium, zinc, copper, selenium.
26 Tests for active metabolite 10-Hydroxycarbazepine.
27 Hereditary Neuropathy.
28 VDRL and VDRL/TPHA have now been replaced by Syphilis IgG/IgM.
29 Optional PAP Smear as additional test
30 Collect sample at end of exposure.
31 At end of shift.
32 Avoid seafood and fish for 2-3 days before collection.
33 Sample must be labelled by hand with first name, family name, gender and date of birth detailed on sample and form. Do not use labels other than the tube label.
34 Samples must arrive in the laboratory on the same day of sample taking or contact the laboratory.
35 Patient should be fasting and resting for 30 mins before sample taking. Samples need handling urgently.
36 Renin: Sample collected either upright/active or resting/supine (3 hours lying). EDTA Plasma must be frozen within 2 hours.
37 Provide sample time and date of collection.
38 EDTA sample should not be separated: send whole blood.
39 Urgent samples have a 3 day TAT if genotype is required for prenatal diagnosis or two weeks TAT if urgent for other factors.
40 Informed Consent is required for these tests. 
41 Recommendation for patient to attend Patient Reception for sample taking.
42 LGV can be added to a positive chlamydia sample using the same swab if requested within 4 days of receipt of result.
43 Please contact for details for referring samples to the laboratory for sequencing testing.


Updated Monday, 20 November 2023