1. We are reporting percent recovery alongside the prolactin result, with a comment to suggest whether there is significant amount of monomeric prolactin. Initially we just provided a comment, but as education seeped through the percent recovery was added.
2. we report that there is a macroprolactin present and that this is believed to not have any physiological activity. Usually I indicate that the active portion will be close to whatever the PEG result was. Not certain that my col! leagues do this latter part.
3. We only report the % recovery after PEG precipitation although the PEG result and the 1:1 diluted control are on the computer as supressed results.
Added comments are as follows :
macro% > 60
Prl recovery shows insignificant macroprolactinaemia.
macro% <40
Prolactin recovery <40 % indicates the presence of significant quantities of macroprolactin which has little biological activity and an apparent hyper-prolactinaemia is probably not significant.
otherwise :
Prl recovery indicates macroprolactin may be present.
4. We report the original Prolactin result, % recovery and the calculated monomeric prolactin, as recommended by NEQAS and others, as well as a commenting on whether this is consistent, or not, with the presence of significant macroprolactin. Reporting the monmeric prolactin has confused our Endocrinologist and other clinicians as we don't have a reference range for this. In retrospect I think it is best not to report monomeric prolactin unless you have a reference range for it.
5. We provide a total result plus a text comment only depending upon whether there is more or less than 50% precipitation . We use the Roche method, which is currently one of the more susceptible assays. However I gather they are bringing out an 'improved' assay very shortly that is said to be much less affected by macroprolactin.
6. We report the monomeric prolactin + macroprolactin positive / negative for all prolactins >700. I don't think it is sensible to report the total prolactin if the patient is positive for macroprolactin. We have a standard "canned" comment we add as as follows: "NB: This patients serum tested positive for Macroprolactin. Macroprolactin is a complex of IgG and prolactin aggregates that has immunochemical activity in vitro. It is generally considered not to be significant pathologically. The above prolactin result has been assayed after these aggregates have been precipitated. I would be happy to discuss if required." This is use across Lincolnshire / Path Links laboratories, regards,
7. we report the % recovery but only report the estimated monomeric prolactin if we have detected macroprolactin i.e. if recovery was <40%. This is because there is a chance that macroprolactin can coexist with genuine hyperprolactinaemia, so if we calculate the estimated monomeric prolactin and it is still >500 then the patient still needs to be followed up. We decided not to report estimated monomeric prolactin on all patients as we thought this would confuse them. We use the Bayer calculation: recovery result x 2.7 to get the estimated monomeric prolactin, as they have validated this to account for the loss of monomeric prolactin in the PEG precipitation procedure. The article I wrote for clinicians is attached if it may be of s! ome use,
8. We report % recovery with a comment, stating the absence or (partial) presence of macroprolactin.
9. We report the monomeric prolactin result and then add an explanatory comment about the macroprolactin being positive in that sample and what that means in the clinical context. We also have a "Macroprolactin" field on the computer which we report as "Positive"-this is a reportable result which automatically triggers the above "auto canned comment". We can then instantly see whether the patient has been tested previously. Hope this makes sense.
10. We have had a lot of problems reporting this in a manner which doesn't cause confusion to the requesting clinician. We currently only report the Macroprolactin investigation results to the Endocrinologists and to any other requester where the screen is positive. Negative screens from Clinicans other than Endocrinologists are not reported, although the results are stored on the Laboratory dat! abase. We are using comments similar to those below.
MPROL recovery 40-60%
There may be the presence of Macroprolactin in this sample. Macroprolactin is prolactin which is bound to Immunoglobulin and this complex has a longer half-life in the blood. After PEG treatment of the sample, a recovery of prolactin in the range 40-60% may be suggestive of the presence of a Macroprolactin. The recovery of prolactin for this sample was XX%. After removal of the Macroprolactin using PEG precipitation, an estimation of the level of monomeric prolactin in this serum sample is XXX miu/L.
MPROL Recovery < 40%
The majority of the prolactin in this sample is Macroprolactin. Macroprolactin is prolactin which is bound to Immunoglobulin and this complex has a longer half-life in the blood. After PEG treatment of the sample, a recovery of prolactin of <40% is suggestive of the presence of a Macroprolactin. The recovery of prolactin for this sample was X! X%. After removal of the Macroprolactin using PEG precipitation, an estimation of the residual monomeric prolactin level in the serum is XXX miu/L.
MPROL Recovery < 60% - report to Endocrinologists only
There is no evidence for the presence of Macroprolactin in this sample.
I would be interested to hear of any feedback you may have received from other laboratories.
11. We sent a letter to all GPs and spoke to endocrinologists.
The original prolactin is reported with a comment to say "macroprolactin to follow".
Once done, this is reported either as "Not detected" or "Macroprolactin detected. Recovery following PEG precipitation = X %. Calculated monomeric prolactin = X mIU/L"