Contents
The Christchurch Endolab group of laboratories offer both
a hormone measurement and a consultation service.
The scientists encourage technical enquiries
about the tests and the specialist physicians and
endocrinologists are available to make clinical comment on results for
both diagnosis and treatment.
Contact can be made by a toll-free phone call (within New Zealand)
to 0800 ENDOLAB or by e-mail .
The Endocrinology, Canterbury Health Laboratories and Nuclear Medicine
laboratories are IANZ registered.
Routine Tests:
These may be requested by filling in the Endolab request
form, or any other Laboratory request form, and following the individual
sampling and transport instructions provided in the alphabetical
listing of tests.
Urgent Tests:
Requests for urgent tests must be made by phone (0800
ENDOLAB) or fax (03 3640 818). The following information is essential:
- when the result is
required
- who it is to be sent
to
- the
phone/fax/pager/beeper number of the recipient.
Research Tests:
Endolab laboratories can offer a service for samples from
research projects, and these requests need to be submitted to the Endolab
Quality Group for approval and budgeting prior to samples being taken.
Discounts are usually available for batch or bulk processing. Payment will
normally be by monthly account, but lump sum pre-payments can result in
further discounts. Please inquire about tests not
listed.
Other Tests:
A few tests are not offered on a routine basis but may be
available after communicating directly with the laboratory concerned.
Adequate justification for the test needs to be provided.
Pads of Endolab forms are available free from Endolab,
although any laboratory requisition form may be used.
The requisition form used should indicate clearly:
- Patient details
- Time & date of
collection
- Address for return
of results
- Address for
invoicing (if appropriate)
- Brief clinical
details
- Tests requested
- Conditions of
sampling (if appropriate)
- Current drug therapy
Conditions of sampling:
Other important factors affecting the level of the hormone
being assayed (see sections on individual hormones) should be noted, e.g. -
posture or sodium content of the diet (renin and aldosterone), or whether the
patient is unduly stressed (ACTH, cortisol, growth hormone) or faint and/or
nauseated (AVP).
Current Drug Therapy:
This should be noted. For example:
- Glucocorticoids
affect ACTH and cortisol values.
- Phenothiazines,
L-dopa, metoclopramide, affect prolactin.
- Contraceptive and
hormone replacement steroids may affect LH, FSH, thyroxine, cortisol and
oestradiol.
- Diuretics, beta
blockers and ACE inhibitors affect renin and sometimes aldosterone.
- Carbimazole, iodine131
or thyroid surgery should be mentioned when requesting thyroid function
tests.
Blood:
We recommend collecting blood into EDTA tubes (mauve top)
as the EDTA tends to inhibit proteolytic enzymes and since our reference
ranges are established using EDTA plasma. For the possible effect of other
anticoagulants on hormone levels, see the table of
significant anticoagulant effects.
It is recommended that all samples be deep-frozen after separation from
the red cells and be held at a temperature of -15°C or lower prior to being
despatched. In general, peptide hormones are rapidly destroyed by plasma
enzymes and therefore ideally the plasma should be separated from the red
cells by centrifugation and be frozen in a separate tube within 15 minutes of
collection. If this is not possible, see the table of
how long separated samples are stable for non-frozen.
As it is not possible for us to aliquot the plasma sample after it is
frozen please provide a separate frozen aliquot for each analyte requested.
Considerable delays may occur if multiple measurements are requested on a
single frozen sample.
Some samples must remain frozen until they are assayed. Refer to the
specific instructions given for individual tests.
Please note that haemolysed samples may give unreliable results and
may not be assayed by the laboratory. Never freeze whole blood as this
causes complete haemolysis, making analysis pointless.
Check with Endolab before submitting samples that may be radioactive, that
is to say from patients who have recently had a radioisotope administered to
them. Such samples are not suitable for many of our tests.
It is essential that all samples should be clearly labelled, with labels
which do not come off in water. Labels must include patient's name, initials,
the date (and time if more than one sample has been taken within 24 hours) and
the type of sample ("S" = serum, "E" = EDTA plasma, "L" = Li heparin plasma, etc).
Whole blood draw volumes = 2.5 times the plasma volumes, e.g. 2.0 mL
plasma requires 5.0 mL blood to be drawn.
Urine:
24 hour collections are usually necessary, but some assays
(e.g. pregnanediol) may be done on random urine samples. Details regarding
the volume of urine necessary and preservatives are given under individual
hormones.
Please label sample with:
- Patient's ID details
- Collection date
(e.g. 24h urine September 16-17 2007).
- 24 hour urine volume
(where necessary), on both the container and the request form.
- A "U" to indicate
that the sample type is urine.
The sample should be stored frozen until despatched to the Endolab.
Some samples must be sent frozen but others may be sent cold (on ice) or
at ambient temperature. See the table of the
duration for which different hormones are stable at different temperatures.
It is essential that approved leak-proof plastic containers be used for
transporting samples. Regulations control the way in which specimens are
transported. NZ Post will no longer accept any diagnostic specimens for
delivery. They may be sent by courier instead. IATA (International Air
Transport Association) now regulates the packing and labelling required for
air transport of specimens or infectious material. Additional regulations
cover the carriage of dry ice (solid CO2). ESR-NZ (Environmental
& Scientific Research) regulates the packing requirements for land
transport of specimens and/or infectious materials. Please contact us if you need assistance with sample
transport.
Infectious Samples:
Samples known to be from infectious patients (i.e. with
HEPATITIS or HIV) must be labelled "INFECTIOUS" and transported
inside a separate plastic specimen bag, with the form in the outer pocket.
Infectious sample transport must also comply with IATA and ESR
regulations.
Note however that where the patient is not known to be infectious, parcels
should be labeled "DIAGNOSTIC SPECIMENS".
Ambient Samples:
It is recommended that leak-proof plastic tubes are used
and wrapped in bubble-wrap with sufficient absorbent material. Ambient
samples must reach the laboratory within five days of sampling.
Frozen Samples:
Where deep-frozen samples are specified, a polystyrene box
or equivalent type of insulated container should be used together with an
outer cardboard box. Dry ice packed around the sample is the ideal medium.
Dry Ice (solid CO2) is regarded as a hazardous substance when
transported by air, and packages must be labeled to IATA regulations to
indicate its presence.
Alternatively use "Pink-Ice" (ice cubes or bricks made from 20%
ammonium chloride (w/v) in coloured water). This is available from Endolab
and keeps samples at -15°C. Be sure that paper-labeled tubes do not come into
direct contact with ice cubes and the outer container is water-tight. Contact
Endolab 0800 ENDOLAB for details of ice volumes and related transport times.
The use of pure water ice cubes, domestic Slikka/Polar packs and such like
has proved to be unsatisfactory.
Delivery Instructions:
Unless delivery to the laboratory door has been
pre-arranged, please free-phone or fax in advance to Endolab, stating the
flight number, date and ETA. The polystyrene boxes will be returned to the
laboratory of origin.
The Endolab group of laboratories are all situated on the Christchurch Hospital site. Because of this, there
is no need to prepare separate parcels for each laboratory as the contents
are easily and rapidly distributed between laboratories.
Patient results are reported on the Delphic system.
Reporting frequencies are listed on each assay data sheet. Many results are
reported within one working day of the sample being received. Other results
can take longer. Urgent results will be telephoned or sent via facsimile to
the number indicated on the requisition form. The requester must contact the
laboratory at the time of sample collection to confirm the degree of urgency.
Current reference intervals are provided on all result
forms and are intended to include 95% of the reference population. These may
be subject to differentiation by age, sex or BMI where important/available.
The reference population for most tests is approximately 200 adult volunteers
who were chosen randomly from Christchurch
electoral rolls, staff and volunteers.
It is emphasized that the reference intervals for hormones and results
published by different laboratories are not directly comparable as these
depend on the hormone standards, antisera and methods used.
Some results are reported with an analytical uncertainty.
This is a calculated 95% confidence interval and refers to measurement error,
not the reference interval. The true measurement error may be larger than
that calculated.
Where the molecular weight of a hormone is accurately
known (e.g. steroid and thyroid hormones, insulin, C-peptide) results are
expressed in SI units of amount (moles per liter). Other peptide hormones are
reported in terms of the appropriate International Reference Preparation in
gravimetric or biological activity units per litre.
|
milli (m)
|
one thousandth (10-3)
|
|
micro (µ)
|
one millionth (10-6)
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nano (n)
|
one thousandth of a millionth (10-9)
|
|
pico (p)
|
one millionth of a millionth (10-12)
|
|
femto (f)
|
10- 15
|
|
g
|
gram
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L
|
litre
|
|
mol
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mole
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M
|
molar (= mole/L)
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SCREENING TESTS FOR COMMON ENDOCRINE
DISORDERS
Addisons
Disease:
Synacthen
test, plasma ACTH, renin, aldosterone, adrenal androgens.
ACTH Deficiency (as in hypopituitarism):
0800h plasma cortisol, synacthen test
(may be normal), hypoglycaemia (eg ITT), metyrapone test.
Adrenal Suppression (patients on steroids):
Synacthen
test, withholding morning prednisone dose until test completed. (If
response subnormal, hold prednisone dose at 3mg, or hydrocortisone dose at
15mg, until synacthen
test, repeated at approx. monthly intervals, is normal).
Congenital Adrenal Hyperplasia:
Plasma 17-OH progesterone (if indicated, during synacthen test).
Plasma ACTH and renin. Usually should be measured in early morning (before
1000h) along with plasma cortisol.
Conn's
Syndrome:
Forenoon (preferably
before 1000hr) plasma renin and aldosterone, preferably in absence of beta
blockers and ACE inhibitors. Patient must have been standing for at least 30
minutes. Measurement of plasma potassium is helpful in the interpretation of
the aldosterone levels.
Cushing's Syndrome:
24hr urine cortisol, 1mg
overnight dexamethasone suppression test. Plasma ACTH for differential
diagnosis.
Phaeochromocytoma:
Plasma catecholamines (30
min supine). Urine (in acid) for free catecholamines and metanephrines.
Virilising Disorder
Plasma testosterone,
SHBG, DHEA sulphate, cortisol (if indicated)
CALCIUM PROBLEMS
Hypocalcaemia:
Plasma parathyroid
hormone, 25(OH)-vitamin D, ionised calcium.
Hypercalcaemia:
Parathyroid hormone, (if
normal, PTH related peptide, 25(OH)-vitamin D).
Paget's disease, increased bone
turnover:
Osteocalcin.
GLUCOSE (ISLET CELL) PROBLEMS
Hypoglycaemia:
Plasma insulin (after
overnight fast or during hypoglycaemic episode), measure glucose on same
sample as insulin. C-peptide measurement will distinguish between endogenous
and exogenous sources of insulin.
GONADAL PROBLEMS (FEMALE)
Amenorrhoea/Menstrual Disturbance:
LH, FSH, prolactin,
oestradiol. If prolactin raised, free thyroxine index. Tests for hirsutism if
indicated.
Menopause:
Raised LH & FSH,
low oestradiol may indicate that the patient is perimenopausal. Considerable
fluctuations may be seen over many months until the patient is truly
menopausal. Patients receiving HRT will usually show a fall in LH and FSH,
but symptoms and bone density are probably better parameters to monitor.
Hirsutism:
Basic screening:
plasma testosterone, sex hormone binding globulin.
Additional tests: LH, FSH, adrenal
androgens (e.g. DHAS), 17-OH progesterone. Tests for Cushing's
if indicated.
Infertility:
Tests for ovulation
Ovulation profile - multiple urine samples, inquire.
Plasma progesterone, one or more samples between days 21-24 of the cycle.
(First day of menstruation = day 1).
Urine pregnanediol, early morning sample, every 4th day from day 1 to next
period. For other tests, see Amenorrhoea and Hirsutism.
GONADAL PROBLEMS (MALE)
Gynaecomastia:
Plasma oestradiol,
LH, FSH, prolactin, testosterone, sex hormone binding globulin, beta-HCG,
alpha-foetoprotein.
Impotence:
Testosterone, sex
hormone binding globulin, prolactin, LH, FSH.
HEART PROBLEMS
Heart failure:
BNP (brain natriuretic
peptide).
HYPERTENSIVE PROBLEMS
See Conn's syndrome, Phaeochromocytoma and
possibly Cushing's Syndrome.
PITUITARY PROBLEMS
Hypopituitarism:
Free thyroxine index,
LH, FSH, prolactin, oestradiol, testosterone, plasma cortisol (8am), 24hr
urine cortisol, Synacthen test,
plasma IGF-1, alpha-subunit. Additional stress tests (eg hypoglycaemia,
metyrapone) may be needed to assess ACTH and cortisol status.
Galactorrhoea/Amenorrhoea:
Plasma prolactin. If borderline, repeat half hourly x 3
with indwelling needle, patient resting.
Cushing's disease:
See Cushing's Syndrome.
Acromegaly:
Plasma IGF-1, hourly plasma growth hormone profile.
(Consider glucose suppression, and TRH tests). Usually IGF-I is a sufficient
screen.
Short/tall stature:
Plasma IGF-1, IGFBP-3.
Short stature
Plasma growth hormone during stimulatory tests (clonidine,
hypoglycaemia, sleep, exercise).
THYROID PROBLEMS
Hypothyroidism:
Free thyroxine index,
TSH.
Hyperthyroidism:
Free thyroxine index,
TSH, triiodothyronine. If the diagnosis is confirmed, thyroid scan is
recommended. (Nuclear Medicine Dept, Christchurch Hospital).
NOTE
Some hormones, e.g.
ACTH, aldosterone, catecholamines and PTHrP require special collection
conditions. The nurses in the Endocrine
Test Center,
Ward 26, Second Floor, Riverside Block, Christchurch Hospital
will ensure that special test procedures and sampling are carried out
correctly.
Endolab
Quality Manual REC-26 / Canterbury
DHB / 29 August 2008/
E-mail to ENDOLAB
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