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Bill Bartlett wrote: > Does anyone have opinion, or hard evidence, as to the utility of prolactin > measurements in the fit versus pseudo-fit scenario? > > Dr WA Bartlett > Consultant Clinical Scientist > Clinical Biochemistry > Birmingham Heartlands Hospital > Birmingham B9 5SS > > Tel. No. 0121 766 6611 Ext 5461. > Mobile 0374 103338 Our laboratory provides, amongst other things, a routine service to an adjacent supra regional neurology centre (HPNC) and I have have been providing this test for a number of years using finger prick blood spots. I am glad to share experiences, and would be interested if anyone else has adopted an similar, or different, approach . The main problem with the test is collecting samples at the right time. The peak rise occurs after 20-30 minutes but by 60 minutes the prolactin has just about returned to normal, so it is easy to miss it and record a false negative, for example in casualty. If the patient is admitted, sometimes there is a long wait for a fit and often EEG is available to help establish a diagnosis.These are probably the main reasons it isn't used much in the hospital setting. Nevertheless neurologists do find it difficult to be sure of the diagnosis of epilepsy, a label which can have serious medical and social implications for the patient. Rather like hypoglycaemic attacks, it is sometimes hard to be sure about a fit which only has been reported when the patient is away from clinical observation. For the last four years we have offered the test as a kit method to enable the patient to collect samples at the time of a fit. They (or their partners) collect on card a baseline blood spot, one 20 minutes after the start of the attack and another after at least 60 minutes (which should confirm the baseline result). The prolactin is eluted and measured. The test seems reliable and the analyses are quite simple and reproducible, if a little time consuming. They do depend on having an analyzer that can cope with the dilute eluents, We currently use a TOSOH AIA21 (Eurogenetics). We did audit the test with the neurologists after a couple of years, but since then have not actively promoted the test. My opinion is that this is useful, and perhaps as importantly so do our neurologists, (or presumably they would not keep taking the trouble to contact me asking for kits to be sent to their patients). I currently send out a few kits per month. However only a minority are returned by the patients with blood spots for analysis, sometimes after considerable delay. How keen the patient is to do the test, of course, may also be informative to the clinician in some cases. As far as hard evidence goes, before the audit I pulled together a bibliography of about 50 papers, which show a high degree of agreement, so there is little doubt that the effect is genuine. It is distinct from non-specific stress effect which also of course can raise prolactin, as well as other hormones, but which doesn't cause the typical rapid rise and fall. (I am sure Medline or another web search would produce a similar list of references.) Unfortunately most are small studies involving a handful of patients which would not meet the current definition of hard evidence. Furthermore, they almost all use different cut-offs making generalisations about sensitivity or specificity difficult. The cut-offs can be either hard, such as a numerical cut-off or a percentage increase over baseline, or soft (e.g. mean +/- x sds). The hard cut-offs are more practical for routine use. There are remarkably few reported cases of normals or pseudo seizure exceeding any reasonable cut-off level, while most false negatives have been just below a high cut-off (e.g. 800 or 1000 mU/L). We adopted a cut-off of a rise of 2.5x the baseline (or 60 min+) and a rise at 20 min to at least 500 mU/L. This allows for a grey borderline area when only one criterion is met. My feeling is that there is a gradation of degree of rise depending on the type and severity of the epilepsy. Unfortunately it would be difficult to get enough cases to produce a definitive study. Apart from patient compliance, the main worry with a negative result is that the timing of the peak sample may be wrong. A 'classic' steeple type response is pretty convincing, but a negative result needs to be treated cautiously because of the timing difficulty. Nevertheless a negative finding can be useful to the physician. To give one anecdote, one of our neurologist felt a certains patient's epilepsy was not genuine but the patient was threatening medical legal action if he withheld antiepileptics. The finger prick test showed an absence of prolactin rise, 'objective' support of his clinical diagnosis for which he was no doubt grateful. So overall, my vote is - not a perfect test but it can help. regards Steve Dr Stephen Frost Principal Biochemist The Princess Royal Hospital Haywards Heath West Sussex UK [log in to unmask] %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%