Evidence-Based Supplement & Herb Guides

Lithium Level and Kidney Function: Interpreting Therapeutic Drug Monitoring

Learn how lithium levels, kidney function tests, timing, therapeutic ranges, and toxicity symptoms are interpreted during lithium therapeutic drug monitoring.

Lithium can work very well for bipolar disorder, but it needs careful blood test monitoring because the useful dose and the harmful dose are...

Manganese Blood Test: High Manganese, Normal Range, Exposure, Toxicity, and Results

Learn what a manganese blood test measures, what high manganese may mean, normal range issues, exposure sources, toxicity symptoms, and follow-up after abnormal results.

A manganese blood test measures the amount of manganese circulating in the blood, usually to help evaluate possible overexposure rather than routine nutrition. Manganese...

Mercury Blood Test: High Mercury, Normal Range, Exposure, Toxicity, and Results

Learn what a mercury blood test measures, what high mercury levels can mean, normal range basics, exposure sources, toxicity symptoms, and when follow-up testing matters.

A mercury blood test measures the amount of mercury circulating in your blood, usually to check for recent or ongoing exposure. It is most...

Mercury Blood Test vs Hair Test: What Is the Difference?

Learn the difference between mercury blood and hair tests, when urine testing is needed, what each result can show, and how exposure source affects interpretation.

Mercury testing is most useful when the test matches the type and timing of exposure. A mercury blood test usually shows recent or ongoing...

Methanol Blood Test: Toxic Alcohol Poisoning, High Levels, Vision Risk, and Results

Methanol blood testing helps diagnose toxic alcohol poisoning, interpret high levels, assess vision risk, and guide urgent treatment with antidotes, bicarbonate, and dialysis.

A methanol blood test measures the amount of methanol, also called methyl alcohol or wood alcohol, in the blood. Methanol is found in some...

Methemoglobin and Carboxyhemoglobin: Interpreting Abnormal Hemoglobin Toxicity Tests

Learn how methemoglobin and carboxyhemoglobin tests are interpreted, what abnormal levels can mean, why pulse oximetry may mislead, and when urgent care is needed.

Methemoglobin and carboxyhemoglobin tests look at hemoglobin that cannot carry oxygen normally. They are often ordered when someone has unexplained low oxygen readings, cyanosis,...

Methemoglobin Blood Test: High Methemoglobin, Cyanosis, Toxicity, Normal Range, and Results

Learn what a methemoglobin blood test measures, what high levels mean, normal range, cyanosis symptoms, common toxicity causes, and when urgent treatment is needed.

A methemoglobin blood test measures how much of your hemoglobin has changed into a form that cannot carry oxygen normally. Hemoglobin is the protein...

Methotrexate Blood Test: Drug Level, Toxicity, Clearance, Therapeutic Monitoring, and Results

Learn what a methotrexate blood test measures, how drug levels guide high-dose methotrexate clearance, what toxic or delayed results can mean, and when follow-up care matters.

A methotrexate blood test measures how much methotrexate is still circulating in the blood after a dose. It is used most often after high-dose...

Nickel Blood Test: High Nickel, Normal Range, Exposure, Toxicity, and Results

Learn what a nickel blood test measures, what high nickel may mean, how normal ranges vary, and when exposure, allergy, toxicity, or follow-up testing matters.

A nickel blood test measures the amount of nickel circulating in the blood, usually to check recent or ongoing exposure. Nickel is a naturally...

Phenobarbital Blood Test: Therapeutic Range, Toxic Level, Seizure Medication Monitoring, and Results

Learn what a phenobarbital blood test measures, common therapeutic and toxic levels, when seizure medication monitoring is needed, and how results are interpreted.

A phenobarbital blood test measures how much phenobarbital is in the blood so a clinician can see whether the dose is likely to control...

Phenytoin Blood Test: Therapeutic Range, Toxic Level, Seizure Medication Monitoring, and Results

Learn what a phenytoin blood test measures, the usual therapeutic range, toxic level signs, total vs free phenytoin results, and how monitoring guides seizure medication safety.

A phenytoin blood test measures the amount of phenytoin in the blood to help keep seizure treatment in a safe and useful range. Phenytoin...

Platinum Blood Test: High Platinum, Exposure, Toxicity, Normal Range, and Results

Learn what a platinum blood test measures, what high platinum may mean, how exposure and chemotherapy affect results, and when follow-up or urgent care is needed.

A platinum blood test measures the amount of platinum in a blood sample. It is a specialty toxicology test, not a routine wellness marker,...

Salicylate Blood Test: Aspirin Toxicity, High Levels, Overdose, and Results

Learn what a salicylate blood test measures, how aspirin toxicity levels are interpreted, when repeat testing matters, and when high salicylate results need urgent care.

A salicylate blood test measures the amount of salicylate in the blood, most often to check for aspirin poisoning or to monitor high-dose aspirin...

Sirolimus Blood Test: Therapeutic Range, Toxic Level, Transplant Drug Monitoring, and Results

Understand the sirolimus blood test, trough timing, therapeutic ranges, toxic level concerns, transplant monitoring, drug interactions, and how results are interpreted.

A sirolimus blood test measures the amount of sirolimus, also called rapamycin, in whole blood. Sirolimus is an immunosuppressant used after kidney transplant and...

Tacrolimus and Creatinine: Interpreting Transplant Drug Monitoring

Learn how tacrolimus trough levels and creatinine are interpreted together after transplant, including target ranges, kidney risk, drug interactions, timing, and when to call the transplant team.

Tacrolimus helps protect a transplanted organ by lowering immune activity, but the dose has to stay in a narrow range. Too little can raise...

Tacrolimus Blood Test: Therapeutic Range, Toxic Level, Transplant Drug Monitoring, and Results

Learn what a tacrolimus blood test measures, how trough levels are timed, what therapeutic and toxic ranges can mean, and how transplant teams interpret results.

A tacrolimus blood test measures the amount of tacrolimus in whole blood so a transplant team can keep the dose strong enough to prevent...

Thallium Blood Test: High Thallium, Normal Range, Poisoning, Toxicity, and Results

Learn what a thallium blood test measures, how high thallium results are interpreted, common normal and toxic ranges, poisoning symptoms, urine testing, and urgent follow-up.

A thallium blood test measures the amount of thallium in the bloodstream after a possible exposure to this toxic heavy metal. Thallium is not...

Theophylline Blood Test: Therapeutic Range, Toxic Level, Asthma Medication Monitoring, and Results

Learn what a theophylline blood test measures, the usual therapeutic range, toxic levels, timing of the sample, causes of high or low results, and when symptoms need urgent care.

Theophylline is an older asthma and COPD medicine that can still be useful for some people, but it needs careful blood level monitoring because...

Therapeutic Drug Monitoring (TDM) Panel: Medication Levels, Therapeutic Ranges, Toxicity, and Results

Learn what a therapeutic drug monitoring panel measures, how peak and trough medication levels are interpreted, and what high, low, or toxic drug results can mean.

A therapeutic drug monitoring panel measures the amount of certain medicines in the blood so the dose can be adjusted safely. It is used...

Therapeutic Drug Monitoring Panel: Interpreting Peak, Trough, and Toxic Levels

Learn how to interpret a therapeutic drug monitoring panel, including peak, trough, random, therapeutic, and toxic medication levels, with timing tips and common drug examples.

A therapeutic drug monitoring panel measures selected medication levels in blood so treatment can be adjusted with more precision. It is most useful for...